I found Ocotillo Rd to have a pretty deep wash to cross with no bypass at 1 1/2 miles from the turn off. It was filled with fairly deep sand that would require 4 wheel drive and aired down tires to cross. I walked the remaining 4mi to the powerlines.
Riggs Road is further south, but on the route to Quartz Peak (the only official trail in the area), so it sees a lot more usage. As such, it was in very good shape (December 2015). The first half of it is paved. From the east end of Riggs Road, one can go north on the powerline road to the intersection with Ocotillo "Road" and go east from there to the trailhead. Both the powerline road the extension of Ocotillo Road were 4WD roads, but not bad.