This trip was highly recommended by some folks familiar with Utah desert hiking. Most of this trip is part of the Hayduke Trail Passage 3 and is supposedly the most difficult part of the Hayduke. Some people claim that the Dark Canyon Wilderness makes a good hot weather hike. I disagree if you ever intend to leave the main canyon of Dark Canyon. It turned out to be one of my most grueling trips ever, mainly due to the extreme heat and lack of defined routes.
Day 1: Drive the 9 hrs to the new trailhead (perhaps it was moved within the last 10 years?) and hike down the Sundance trail to Dark Canyon. I put the pack on and am on trail by about 4:45 PM (Utah time) The trail is initially a 4x4 road and the turnoff onto the trail section is fairly well marked. The trail across the plateau is fragmented and I pick one of the more popular routes and do indeed find the beginning of the downclimb. Most people complain that the trail is steep. The steepness is there but what is more difficult is that you are basically descending a boulder slope, and too many people have taken shortcuts and caused erosion to make the trail steep. There are some original sections that are moderate grade, but they are hard to find as there are dozens of cairned paths down the crappy slope. The advice I received to hike the trail in late afternoon was accurate as I had shade for the entire downclimb. Once at the bottom I took the more popular trail (there are about 2) straight to the creek of Dark Canyon and setup camp on a nice campsite just at sunset. The temperatures were still very warm (perhaps 85 at sunset) and I was able to enjoy dunking in the creek to try to clean up and cool off. So far so good. When I didn't need the sleeping bag until about 2AM, I realized that I was in for a hot trip, and that the forecasts of planned cooler weather were wrong.
Day 2: Pack up camp and hike upstream along the main creek of Dark Canyon. There is some trail but for the most part you just hike the rock along the creek. It is interesting geology and the hiking is not generally difficult, until you have to find a bypass around some of the more difficult obstacles. One of the main things I noticed was that the canyon appeared to have a major flash flood within the last year. Debris was piled high in several sections, and I think it washed away the rockpile used on one of the more critical bypasses. Along the way I felt fortunate to run into some bighorn sheep. I dunked in the creek several times to try to control body temperature, but I also had to take numerous shade breaks due to the unrelenting sun. I did make it the approximately 8 miles to Young's canyon. Young's canyon has a beautiful waterfall right at the mouth, but to access it you have to wade through deep water and deep muck. Furthermore, the route up Young's canyon was not obvious. When I finally figured it out, I spent over an hour deciding whether to abort. The climb looks formidable, and I first climbed it without my pack as I was worried I couldn't climb it with the pack. The climb is perhaps class 4 minus right next to the waterfall, and I also tried another route that didn't pan out a little further away. I also figured out that my first attempt was more difficult than it had to be.
Tips for making the climb easier:
1) use the Young's canyon water to clean every last bit of the muck off your shoes.
2) Climb the route right next to the waterfall after it is dry, don't try to climb after it is muddy or wet from someone's previous climb.
3) The most difficult part is the 2nd-3rd step up onto a sloping section, once you get past that keep climbing efficiently and don't stop, or you may begin to slide where you made the rock wet.
Once up Young's I admired what is known as the Emerald pool and hiked further upcanyon to a nice open area. I didn't need a sleeping bag at all that night.
Day 3: The plan was to climb out Youngs Canyon, over to Lean-To, and descend Lean-to Canyon, about a 13 mile day with perhaps 2000 ft AEG. It didn't quite work out.
There are some sections of trail in lower Youngs but mostly it is a rockhop up the canyon. There are 3 main bypasses when climbing up Youngs Canyon, and they are all on your right, looking up canyon. The first is a mild climb up about 40 feet, bypassing a section of canyon where a house sized boulder has caused a 20 foot cliff. The second is further up canyon, below a small pinnacle. You want to climb 300 ft up a side canyon 90% of the way and then as it turns out, up another 100 ft to a rocky slope to reach the pinnacle. This bypass is not well marked. Once at the pinnacle you continue up canyon until you can up-climb the final cliff band. I perhaps didn't take the most popular route, as I noticed a trail where people continued further down-canyon on top of the cliff. After this is a good trail you take along the canyon edge bypassing 2 large drops of perhaps 80 ft and 120 ft, and the canyon bottom eventually catches up to you and you return to hiking the canyon bottom. The final bypass is a 600-800 ft climb in which you completely make it to the rim above. This bypass is along mostly good trail, but there was a landslide, and I had to do a class 4 climb to get up a cliff band where it was washed out. When you get to the top there is no obvious trail across the Cedar desert. Just go in the up canyon direction close to the rim, as you later you descend back into the canyon. I found a better route that didn't involve what I refer to as the "hang-glider option" which was the cairned path. By the way, every cairn in Young's canyon is off route, placed by lost hikers, and usually leads to dangerous climbs. The key is to ignore every cairn you find unless you know it is along your intended path. Since I had little idea of the path, it took a lot of searching and backtracking to find the best places. I didn't kick down all the bad cairns, and placed no new ones. Anyway, once back in the canyon you continue to follow it up further as the character changes to more dirt slopes than rock. There are some minor cliffs, with a small cliff bypassed on the left, and the final obstacle there is actually a good trail to the right of it up a slope. When I finally got to the rim I was a few hours behind plan, and lower on water than planned.
I hiked cross country over to Sweet Alice road, and began searching for a trail to drop into Lean-to. I never found a trail and ended up circumnavigating the large area at the top of Lean-To. My plan was to avoid the crypto soil and mainly hike in washes. I ran out of time looking for the trail into Lean-to and camped in a wash after completing what I thought was a reasonable downclimb. It was hot, I was tired and behind schedule, and some of my navigational decisions were questionable. Luckily I found some potholes and was able to obtain about a gallon of much needed water, since at the end of the day I was down to my last liter (I had carried up 2 gallons from Youngs).
Day 4: The morning dawns and I backtrack looking for where I thought the best route down would be. After about an hour I find a cairn and proceed to downclimb, right where I had marked the best downclimb to be. I should have just trusted my research, rather than trying to look for trails in the desert. I thought Lean-to was a slam dunk, but it actually has many cliffs that need to be bypassed, none of which are ever mentioned in the beta I had obtained. There are perhaps 3 major obstacles where Lean-to slots up and forms dryfalls. I think the first bypass was on the right. The second I know is on the right because the start of it is questionable as you are ascending a slope that just barely is level enough to climb, rather than slide off the cliff. You go rather high and down canyon about 100 feet about the canyon bottom until you eventually downclimb down, after about 200 yards. The last obstacle was frightening because of its size and the seemingly impossibility of getting around it. I found part of the bypass, but descended too soon, this bypass actually is on left (LDC) and puts you about 200 feet above the canyon floor with a reasonable downclimb that is hidden from view. At the bottom you run into some beautiful pools where a spring begins. There are reeds and frogs and shade. After this the descent down Lean-to becomes more challenging, but it is more beatiful. I waded most of the rest of the canyon through thigh deep water, and was kind of enjoying myself, as it is an amazing place. However physically and emotionally I was tired of all the unknowns and unplanned difficulties. As you descend down Lean-to the water finally dries up before a 300 ft or so pourover in an amazing arrangement of rock. A good trail is found here on left, and is great to hike on trail (finally) all the way back into Dark Canyon. The trail fragments as people access it from below in different ways, but I took the one that lead straight back to my original campsite.
After setting up camp, I decided to explore down Dark Canyon towards the Colorado. The trail is good for awhile then there is some sections where you hike on benches along the creek. The first bench goes maybe 40 ft above the creek and is pleasant. It then crosses over and you have to do a fingers and toes shimmy along a ledge before you hike on a very good trail along the bench. The problem is that it gets about 150 ft above the creek and eventually it is so steep you cannot see the creek, the waterfalls, or any of the "good stuff" I wanted to see. Also, since you are away from the water there is no way to cool off. I went perhaps half way to the Colorado River before I turned around, not really wanting to continue climbing above and away from the creek. It supposedly returns to creek level, as the trail is probably from rafters coming up canyon.
Day 5: I hike out in the morning. The sun hits the landslide about 9:30 AM so I climb in the sun. It gets hotter but I finish the climb before the hottest part of the day, however it gets pretty toasty as I traverse the plateau back to the road and my vehicle. Surprisingly there is another car parked at the trailhead. Never saw who it was. I also saw another pair of footprints that looked like they went to the top of the landslide and then turned around. Dark Canyon is definitely a place for solitude seekers.
In summary, I would not recommend the Youngs and Lean-To Loop in September. October might bet better - wait for highs in the 70s-low 80s, not in the 90s. Also, I would only recommend this trip to extremely experienced backpackers with some climbing experience, and excellent navigational skills. It is very remote, and in my opinion, very difficult. Just going down Sundance into Dark Canyon is a more reasonable type of trip to the novice backpackers, and perhaps exploring a bit up and down canyon.
Finally, make sure your water filtration is field cleanable, I had to clean my ceramic filter upwards of 40 times over the entire trip. I also probably drank about 9 gallons of water over these 5 days.