In that case, I'll point out that I know of many owners of small, molded-fiberglass TTs who tow them with V6 SUVs. A 3500/350 tow capacity is sufficient for most of those, like 16' Scamp or Casita (but the 17' Casita tends to be too hitch-heavy, over 350 lbs). Besides being easy to maneuver and easier to see around (narrower bodies than most TTs), they have lower wind resistance and you might get around 15 mpg towing them. That's not far from what I got when towing the popups.
The one thing on your list that they may lack is a freezer compartment... I'm not certain. Add a small Truckfridge (the 12V compressor allows setting as freezer) somewhere in your rig and you might be set.