I've never been in the actual campground, but I am told there is a place up there just east of the highway 20 junction...I believe off of the Cisco Grove Off ramp, then onto the north side of the highway...that has camping and is OHV friendly. You can get into the trails up into the Fordyce area etc., good riding. Camping is said to be decent too. You just need to research the Cisco Grove area for camping, perhaps call Tahoe National Forest HQ in Nevada City and they can point you in the right direction.
Remember, in Cali ya gotta wear the helmet, have the spark arrestor, (the training wheels, air bags and parachutes, LOL) and they have LEO up there working it so don't count on a fudge factor) but that is some pretty country up there.