28-30ft fifth wheel boondock/campable in public lands?

Here's a 'Clicky' for an excellent national forest campground list. It will give you the size of the campsites and the road information to get to those campgrounds. It will also give suggestions as to whether you should take a big rig there. We used it all the time.

http://www.forestcamping.com/dow/list/nflist.htm