If I had to guess I'd say you're more likely to be in trouble in a toterhome/gooseneck rig than in an RV/tag trailer combo just because the DOT are going to look more at a rig that is an obvious race rig or potential commerical rig. I know 2 racers that have had issues and one vendor, the vendor had to go to a cdl (of course) but the racers are fine. The DOT peeps were a little lost on the whole idea of amateur hobby racers with rather large lettered rigs but figured it out. None have been pulled over anywhere for length of their rig.
Sean P. Clarke
WERA Motorcycle Roadracing