If you know which places you'll likely to travel to then you can always plan the optimum route(s) with easy on/off rest areas and avoiding those with weigh stations or areas known for zealous LEO's. Also, your total rig would be conspicuous and might beg "measure me!"
The state by state 'advertised' length is linked here...
http://drivinglaws.aaa.com/tag/trailer-dimensions/
Agree on the diesel pusher, wish I had done it sooner. If you're on the road overnight and don't care for WallyWorld or Rest Areas you can use this for finding a spot that can accommodate you without unhooking.
http://www.bigrigresorts.com