Why do you want to downsize?
I think they're way over priced for what you get. You mentioned fuel milage. It will probably be an improvement over a Class C, but unless you're doing 30,000 miles or more a year, how much are you really going to save?
Increased insurance cost on a new and more expensive rig over your Class C will eat up any fuel savings.
I still wouldn't travel without a toad - wouldn't be able to put up with disconnecting everything to go to the store for a can of tomato paste (had to go for one in the Jeep yesterday).
Bill