All the details are at:
http://www.sccxterra.com/xcursion43.html For camping I recommend the national forest areas, anything close to the OHV such as Gold Hill will be noisy, crowded, hot. The higher up the better IMO:
http://www.fs.fed.us/r5/lospadres/recreation/develop-camp/mprd.html Everybody is encouraged to attend no matter what you drive, there is plenty of diversity
The OHV has many different trails to choice from, the trail ride to alamo is 4x2 friendly, and the optional challenging trail on miller is meant for those up for a real challenge/have the equipment such as rock bars.
Hope to CYA
Brian