My TT is 34'. It has been down some jeep trails more than it should have. Fortunantly it survived without rolling over. Not something I recommend.
A normal trip for us will entail quite a few miles of dirt roads of varying difficulty.
My TT has held up well. My Lippert frame is very stout, and is the best frame I have had in any of my TTs... I believe that is because Sabre specified a heavy duty frame, and Lippert delivered.
Occasionally I will drop a quad off the rack to check out a side road before committing to towing the rig in there.
One does have to check the unit over often for loose screws often. I use loctite on every loose one I find, that keeps it from loosening up again.
I figure if I keep it long enough, I will eventually get them all.
:B