Good introduction to what is boondocking: http://www.rv-camping.org/Boondocking.html
“Defines boondocking as remote location “dispersed camping”, and the term “dispersed camping” is defined as “camping outside developed campgrounds”. There is no official definition of the term boondocking however, but overnight RV parking places such as WalMart or truck stops, NASCAR races, federal and state campground, and any time RV hookups are not available (dry camping) have been referred to as boondocking.”
USFS Motor Vehicle Use Maps – http://www.fs.fed.us/recreation/programs/ohv/ohv_maps.shtml
USFS Site – http://www.fs.fed.us/
BLM Site – http://www.blm.gov/wo/st/en.html
BLM Land in AZ for Boondocking Map