I bought a Gulfstream Visa 19 ERD thinking I could tow it behind my 2006 Toyota Sienna.
The van would tow it but it was definitely pushing the maximum capability of the rig with just me and the wife. Also the hitch is so low that I needed a WDH and air bags in the rear coils just to maintain about 6 inches ground clearance for the bottom of the hitch. It towed ok at 60-65 on smooth interstate highways but was easily blown about by passing big rigs, busses, etc. We got about 9mpg and the tranny would downshift a lot from 4th gear (forget 5th) on even the slightest grade ... i.e. overpasses.
We now tow with a Trailblazer ... 5500lb tow rating but shorter wheelbase so the ride isn't as good as the van. Not so much of a strain but we tow in 3rd gear and get about 11.5-12.5 mpg withe the 290hp inline six. Same E2 WDH, but much better ground clearance. Still according to the CAT scales, we're still just shy of the maximum axle loading.
With full sized TTs you're towing a ten foot diameter parachute back there, there's no free lunch. Love the camper though.