Living a couple miles from a Flying J off I-95, 29 miles north of the GA - FL border, we see all types of setups. Truck Campers pulling a TT. Pickups towing a 5th wheel towing a utility trailer with a Golf Cart or the second tow might be a boat. Saw an interesting one Sunday. It was a Peterbilt tractor with a large sleeper. Matted to the sleeper was an old travel trailer sitting on the back half of the tractor. It was a small TT though and there was no overhand.
When we first bought our MH, we did not trade in our HTT. While we were trying to sell the HTT, I moved it around the storage yard with the MH. I don't think I'd be comfortable at highway speeds though.
-Michael