Our Bay Star is in the 33'range and I wouldn't travel in it without having another vehicle for getting around, sightseeing, etc. I don't have any experience with a class C, but having owned a Dodge dually that was about the length of your class C, I'll say that there is a big difference in maneuvering a 21' rig versus 33' class A.
Having owned 2 travel trailers and then getting our Bay Star a little over 2 years ago, I will also suggest that you think about a travel trailer/fifth wheel with a good truck for towing it. I love the advantages of our class A, but even owning a gas class A comes with a price in terms of service and maintenance.
Also, once you get into towing a car, whether 4 wheels down or on a dolly, it can cost quite a bit for the gear and installation. You may be able to save quite a bit if you can handle the installation of a base plate and required wiring.