Just got back from there last weekend.
Probably the most important thing you need to know is that the main road to BB (330) is closed as of this past Monday for construction. You have to go in the back way on 38.
As for trails, there are many fun ones. Try to find the Charles Wells trail guide at Barnes and Noble or someplace, he has several outlined in there with easy to follow directions and tips. Otherwise, the Benchmark California Road & Recreation Atlas is good but even Triple A has a halfway decent BB map that shows the basic backroads of the area.
Most of the trails are stock friendly, but some others are good with a bit of lift, sliders, better tires. John Bull is among the toughest up there with rock gardens that love the feel of armor plate.
Hope this helps. We have some stuff on the SCCXterra.com site that may be helpful as well.