Check out the Mercedes Sprinter Class A ones while you are looking. We love ours and have put about 5000 miles on it since purchasing it in Feb. And we've averaged over 16 mpg so far, with a lot of that thru the mountains. We did go from a slightly larger TT to this but gained a lot of outside storage space and lost very little usable interior space. My wife was always afraid to drive the truck with TT and I had a few white knuckle moments. Recently, while we were returning from a trip to Tenn, I got bronchitus and she ended up driving almost all of the 1000 miles home - she did great. This reminds me of driving a large van.
Good luck with whatever you decide!