If you're not afraid of the signage then here are my notes from March, 2013. (It seems Google maps calls it White House Canyon Rd which may or may not be the same - the following notes were made from actual signage on the ground):
The usual warning signs about possible illegal activities are posted here so, if you are afraid to camp in isolation here, you may wish to pass on them. For those we want a quiet free desert camping experience, here are directions:
Leaving Madera Canyon on Madera Canyon Rd, turn east (right) onto Florida Canyon Rd, a dirt road.
A sign near the entrance tells you it goes to Hwy 83 in 14 miles.
Drive about ยผ mile, then take the first road to the right, Forest Rd 62A. After ยผ mile, a clearing with three fire rings marks the boondocking area on your left. The area is not large but has a great view and could easily accommodate three large RVs.
N31.78748ยบ W110.87212ยบ (Geographic coordinates at this dispersed camping location)
Return to Florida Canyon Rd and continue 1.5 miles farther east, keeping right at the Y to follow Box Canyon Rd.
Watch for Forest Rd 62 and exit right. This road is not as good as the others but doable and you only have to travel ยฝ mile to a small clearing on the right just past a cattle guard. There is a fire ring and enough space for only only one RV. This location is out-of-site of the main road.
N31.77707ยบ W110.84810ยบ (Geographic coordinates at this dispersed camping location)
Although on forest property, the terrain is desert and there is no shade at either location.