particularly if you are going to get a car that can be towed, 4 down is best by far. Ford chassis A's will have a tow rating of 3500-5000 pounds. A trailer will wieght the better part of a ton emptry, and when you get there you gotta find a place to put it. Ditto for the dolly, 'cept it's not as big.
4 down is easy, all you need is a tow bar, lights, and a braking system.Hookup is fast, and there is nothing to store, the tow bar stays on the back of the motorhome when not in use.
Many if not most 4wd vehicles can be towed. A lot of maunaul trans cars can be too. motorhome magazine has a full list on their website.
Always check the car's owners manual under "rectreational towing"
Popular include most jeeps, honda crv's, awd ford escapes, and many saturn models.
The ever popular searching on this and other forums will yeild a host of info.