IMO, Death Valley is the most underrated national park I have ever been to. It is the largest outside of Alaska, and covers more different topographies than anywhere I have seen, at least out of 20 so far. This was our first trip to the park, and despite the 5-6 hour drive each way, we have been there at least four times since, and still have barely repeated any hikes. You are able to go to the lowest point in the western hemisphere at less than -200 feet and then up to 11000 feet in only a few hours. You can see sand dunes, craters, marbled canyons, and waterfalls in the same day. It's truly breathtaking, and almost every time we are there, the place feels deserted. 

Each day of this trip report can be used as a separate set of activities, as they are all grouped geographically.

Friday: The major attractions south of Furnace Creek

1. Golden Canyon Interpretive Trail w/ Gower Gulch loop: 4.0 mi RT. This was the first hike, and by far the most exposed to heat and sun. The canyon walls were interesting, and there is a side trip about 1.0 mi in that leads 0.25 mi to the "red cathedral" with really tall walls and and nice colors. Towards 3.0 mi or so, there are a lot of old mines in the hillsides, where they reach down to within 6 feet of the wash. One of them that was larger, sturdy and actually went through a hill 20 ft to the other side, and had a junction that went further in as well. If you end up doing this trail, make sure to take a map or GPS as some of the trail signs were literally torn out of their holes and scattered along the wash. 
2. Natural Bridge Canyon: 1.5 mi RT to natural bridge. This was neat to see the giant natural bridge, but only do it if you feel like you have plenty of time. There is not much else to see aside from it and some dry falls, the path is uphill and sandy/gravelly, and the dirt road access is one of the more severe ones.
3. Devil's Golf Course: Nice little detour along a dirt road to some interesting salt formations.
4. Badwater EL -282 ft.: Took the short walk into the salt flats, and if you bear right you can find formations that are incredibly well preserved and untouched by tourists. I never would have thought you could have so much fun with macro settings and a piece of salt. Look closely at the photo of the hillside and you'll see the sign indicating where sea level is....
5. Artist's Palette 1-way drive: Desert beauty and fun in many places. Has pulloffs where you can get shots of green, orange, purple, white, and black boulders all next to each other. Worth the 30 minute drive.
6. Dante's View: Had 40 minutes to sunset, so drove all the way over to this lookout point that is actually directly above Badwater on a huge cliff, and provided an incredible view of the valley. Unfortunately the sunset had very little cloud interference to make it truly spectacular.

Saturday: Heading North from Furnace Creek.

Mt. Lyell is the tallest peak in Yosemite NP at 13114 feet, and regarded by many peakbaggers as having some of the most impressive views of the Sierras based upon it's proximity to many other highpoints (with the others being Mt. Brewer in King's Canyon and Mt. Hoffman in Yosemite near May Lake). 

For this trip, Marie and I camped out along Hwy 120 at one of the many small Inyo NF campgrounds on the east entrance, and met up with Aaron at the ranger station early the next morning. We were easily able to nab a walk up permit for backpacking via Lyell Canyon from the Tuolomne Meadows Trailhead. After organizing our gear, we set off for our base camp at the upper portion of Lyell Canyon, just below the tree line. There were 3 or 4 campsites on the west side of the river, which provided plenty of ample water flow still in early September. 

The next morning we awoke leisurely, as the peak was only a few miles away at this point, and hiked up to Lyell pass, the edge of Yosemite NP, before turning west towards the peak. The approach was mostly clear of boulders until the last mile, which began turning into dense scree. We passed a couple who had turned around for fear of some ominous storm clouds, but we were keeping a watchful eye on them the whole time, and in fact didn't hear our first bit of thunder or see any lightning (on another, very distant peak) until we had actually reached our own summit. 
When we reached the large Lyell glacier, we immediately wished we had crampons in our packs, as the trip around them to the north added easily an extra 30 minutes over just climbing straight up the glacier to the final summit approach. There was a point at which due to the distance and perspective of the mountain, it seemed impossible to scale without ropes, and had it not been for Marie pushing us along, we would have never summited. Sure enough, she was right (as she always is) and we found the final summit climb very easy with minimal exposure. The summit was beautiful, and showed an impressive set of afternoon storm clouds in the distance which caused us to go back down with haste. We reached our basecamp well before dark, and leisurely packed out the next day, making for a very enjoyable and relaxed backpacking trip to a beautiful summit. 
Day 1 

Devil's Postpile and Rainbow Falls ~ 5.5 miles. Great hike and well worth it to a unique geological feature, with hexagonal columns up to 60 feet tall. Rainbow falls, albeit not unique was still a very impressive waterfall at 101 feet from base to top of falls. 
Mono Lake South Tufa Area and Panum Crater Plug Trail ~ 2 miles.The tufa (stalagmite-resembling towers of salt) form at the bottom of Mono lake due to the extremely high salinity. This area of the lake has been exposed due to slowly drying up levels of water, leaving these interesting formations exposed. Also visible in this area are the millions of alkali flies that live along the edges of the lake. Yes, that picture of "black" shoreline is actually a bed of flies. Apparently, one of the issues of the past has been people removing pieces of Tufa, hence the very interesting sign. 

After the tufa, we went on to Panum Crater to explore the remains of an old volcanic eruption. Two very interesting types of rock formed under volcanic conditions are Obsidian and Pumice. This was a great opportunity to appear to be 10x stronger than in reality with the amazingly lightweight Pumice that was found everywhere. 
Black Point Hike ~ 3 miles RT, Looking for some slot canyons and fissures in the plateau near Mono Lake, but hard to find the fissures as the instructional sheet of paper from the visitor's center had very poorly designed instructions. They recommended circling the south side of a sandy hill in order to slowly walk up in a switchback fashion. I would suggest going straight up to the peak (perpendicular to the road), and then you can see the fissures from the top. However, the roundabout manner at least allowed us to meet a reptile friend. . They were pretty incredible slot canyons between 1 and 4 feet wide, 10 to 50 feet tall, and in some cases hundreds of feet long. Some of them started and ended in the plateau---as in they did not end at an open cliff. Very enjoyable day hike if you can find them. It was nearing dusk as we finished, and we got treated with a sunset on the way back to the car. 
Day 2

Saddlebag and 20 Lakes Basin Loop Hike ~ 6 miles
in a loop at 10000 feet around a number of lakes just north of CA 120, Tioga Pass Rd. You can make it a couple miles longer by not taking the ferry across the largest of the lakes- Saddlebag. Great examples of alpine scenery. 

The old Mojave Road was the southernmost route used to cross to the west coast by missionaries, the military, and various other groups, starting with Juan Batista de Anza's expedition in 1776. It is a 138 mile trail across the Mojave National Preserve from the Colorado river (and Nevada border) to Afton canyon, just west of Baker, CA (familiar to those Angelinos who make the weekend pilgrimage to Vegas). It crosses through historic forts, near stalactite-filled caverns, past many petroglyphs, lava tubes, cinder cones, early desert settler relics, and large canyons, all along some rough 4x4 roads. If you are interested in repeating this trip, I recommend saving these coordinates on Dirtopia at a minimum, and suggest purchasing Adler Publishing's California Trails - Desert Region book, which has integrated trail directions, GPS coordinates, and lots of information on the various areas you pass through. 

For this trip, we rented a classic 2 door Jeep Wrangler (this was before the FJ Cruiser, and this rental provided me with more reasons of why I didn't want a Jeep as my main car). We left on a Friday late morning and reached the starting point of Needles, CA with enough time to set up our tent at a KOA, grab some dinner and go to sleep. Saturday we began the drive, crossed over the Colorado River, and headed west into the Mojave NP, where we visited Fort Piute and Piute Spring, an old army base with many Native American petroglyphs. There was a Jeep meetup going on at the time, which led us to believe that the road was going to be much busier than expected, but it turned out that everyone only went to the main destinations and didn't travel the Old road, which provided for a much more pleasant trip.

From the Fort, we travelled west over an extremely rough and rocky pass, surprised that we didn't get a flat tire. Unfortunately, being our first offroading and backroad navigating experience, we wound up a few miles too far north, and were skirting a gorgeous canyon in Lanfair Valley before reaching a set of rough stadium jumps and sharp terrain, which did give us a flat tire! After swapping out the spare, we turned around, found the right trail, and at the intersection of Lanfair Valley Road, beared south to reach the nearest tire shop, which turned out to be many miles away, on the south side of I-40, in a "town" called Essex. The town was completely run down with the exception of a post office and a mechanics garage that charged a whopping $5 to fix our flat. 
A couple hours behind, but back on track, we return to the Old Mojave Road where we left off, and head west to Black Canyon Rd, where we spend a night at Mid Hills Campground after viewing one of the most incredible desert sunsets that I have set my eyes on. Nights got fairly cold here, and the fire was a very welcome addition to the evening.
We awoke on Sunday for an adventure-filled day, starting with a ranger-led tour of the Mitchell Caverns State Natural Preserve, within the Providence Mountains SRA. These are some fun little caverns with well preserved formations, sitting in the middle of the Mojave National Preserve. It is also accessible via paved road from I-40, and thus recommended even if you are just passing through.

Friday we left fairly early from LA for the eastern side of Pinnacles National Monument, and arrived at the shady and oak-strewn campground after a long stretch of winding and hilly rural roads. I never get carsick or any other form of motion sickness, but the last couple hours I had been increasingly more and more sick-to-the-stomach. Unfortunately after setting up the tent and air mattress, which we finished fairly early in the afternoon, I was more nauseous than ever. I had overlooked the fact that Marie had previously had a light stomach bug of some sort, and I must have eaten the same thing as her a few days later, because it was a horrible pain. Slowly everyone else arrived and pitched their tents, including Susanne, Justin, and Eric-- who had an amusingly large, rented 8 person fortress tent. I napped and stayed in the tent until dinner when I had a few bites to eat before going back to sleep, still sick.

Saturday morning I woke up feeling slightly improved, but still couldn’t eat anything. The options were to skip the 12 mile loop hike I had planned through both famous caves (and a possibility of bats), to do a small dayhike by myself, or to tough it out. Well if you don’t know me, I’m pretty stubborn, so the third option was the only one. As a result, they were forced to go slowly, but we still had a good time overall. The first cave was not too far in and it was great to crawl through the tight cave (especially being 6’3”), but unfortunately no bats were visibly roosting. We continued the hike to the top of the peak in the middle of the park, and followed some precarious stone ledges around to the other side. This was made easier with some metal pipe railings, but be advised that if you are over 5’10” or so, it is actually more difficult because the railings are at mid-thigh height and just waiting for some over-brave soul to fall over the railing a few hundred feet.
At this point I started feeling worse and they had to go increasingly slower to wait for me, but after descending the other side and reaching the western TH and campground, I drank gallons of water and laid down. Next we hiked through a wash to the second cave and saw some even more impressive drops and descents, but once again no bats. (I was just in a rush to get through it though, so there could have been some). Once on the other side, it was a fairly level hike along a stream back to the TH. I felt increasingly better and better, and by the time we had driven back to the campground I felt good enough to eat a huge meal and enjoy the campfire.