I found some more information about the trail:

http://www.mtbr.com/trails/California-Allotherareas/Peligreen-GrapevineTrail.html

GPS waypoint for the campground:

http://wayhoo.com/index/a/wdet/wid/93565/waypoint/Black+Oak+Grove/ste/California/

BTW, San Jose to Paynes Creek (which is east of Red Bluff) is about a 4-hour drive (244 mi). Just FYI.

Also, do you want to borrow my PETT toilet for the trip? It might be more comfortable than digging a hole.