Hiker's Rule - never judge a hike based on your view of the general environs and gut feeling. You never know how good a hike is until you do it. This is indeed a very nice hike, and fun, with some geology as well. And varied. I would never do it in summer, or if it looks like rain (I'm sure flash floods have to do with the slot formation - and you never know if it looks inclement).
GPS coordinates for intersection of Box Canyon Road (66th avenue) and Painted Canyon Road are Lat 33.575712 / Long 115.996056. The dirt Road ends at the Parking Lot (don't pull off at a parking place until you know your road has ended, i.e. can't go any further). I think it's a little over 4 miles. It is marked. No cars were broken into when we were there. Regarding wash board - In my Kia Sorento, I found that going 35-40 miles an hour on the washboard was more comfortable than going slower. Watch for on-coming traffic, and don't loose control (I have AWD).
Regarding the trail - at .4 miles into the lovely canyon walk, look on your left for the easy scramble on your left to the slot/ladder part. It is marked with a huge rock arrow on the ground, and a small sign on your right - but unbelievably people still miss it. Do the loop clockwise (meaning the slot part first). If your in a hurry, do the slot up, then back the same way. At the very top of the slot/canyon, you will see some radio towers off in the distance. To find the way into the painted canyon on your right, you will head toward the radio towers in the distance. The trail down into the painted canyon is a little over a mile up, and well marked. Note, the last 100 feet into the canyon is steep, for most, you will be on your butt for at least some of it (not dangerous though). Big note though - when you get to the top of the slot area where you can see the radio towers, there will be a trail down on your right overlooking the painted canyon, going downhill (back toward the parking area). At the very end of that trail is a very nice photo-op into the canyon.
Few last notes - bring water. The high desert trail at the top is very dry! There is no greenery and no blooms (California drought). This part can be attractive in wetter years, but looks scorched now. Total elevation gain is 750 feets (top elevation is around 1400 foot elevation). The Salton Sea is apparent from up there.
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