We rode this Jan of 2012 following a route from gpsxchange.com: http://www.gpsxchange.com/phpBB2/viewtopic.php?t=1505
Mostly good two track. Heading into the mountains after La Trinidad the track runs in a very sandy, rocky wash for a ways and would be a stone bitch on a big bike. The area is VERY remote. It took us about 18 hours from Bay of LA, but we had a bunch of mechanicals (leaking tank, broken sub frame, malfunctioning lights, broken chain, ruptured FI hose) and spent at least 4 hours stopped wrenching.