Update as of 12-22-14: I drove in from the South. The turnoff is at mile marker 35 on Hwy 238. This road was in extremely poor condition,very rocky and washed out after the recent rains, in particular the first 5 miles. It's about 10 miles to the turnoff to the trailhead. It took me 2 hours to get there!You will need high clearance 4WD for this road.
On my way back I used the route described here (turning North) and the road was in much better condition, just a bit sandy and with a couple of minor wash crossings. However, there is a road closure at the Riggs/Bullard intersection due to a washed out bridge. I chose to ignore it and you have to drive through a wash to continue which should be no problem unless you are in a little sports sedan.
I found the roads approaching from the North to be in MUCH better condition and will never use the Southern route again as I was lucky not to get stuck or tear up my rig.