Those rules were mostly written for TENT campers - hikers, back packers, etc, not folks towing 15,000 lb fifths with 9000 lb dualies
most of the designated roads you'll find will have no driveable access off the road. the feds lay logs along the roads, as well as a pretty sizable mud berm at the shoulder, at least here in Michigan. you camp where they want you to camp... you'll come along "sites" where the berm is knocked down and the logs cleared and the trees are spaces out a bit more. sometimes the site is big enough for a truck camper, van or small mh... sometimes the site is big enough for 4-5 big rv's.
i suppose you could take a literal interpretation of their rules, shovel the berm down yourself, winch the logs out of the way and forge a new trail, but that's a lot of work.
drive your back roads, two-tracks and fire trails. you'll find sites that are already established. some folks claim they can spot these from google earth. maybe it works out west without a tree canopy? the sites I like to frequent in Michigan, the only way you're finding them is local knowledge and driving the trails.
