Still looking for a tow vehicle.

I am thinking about going with a ford E 250 or 350 van, but have some questions.

Are all the ford vans 2wd or can they be had in 4wd?

How is the gas milage in a van on the HWY? It just doesn't seem to aerodynamic. But at the same time it looks like a van would have an aero advantage over a pickup, if both vehicles were pulling a 24' enclosed it would seem to me that the van would do better.

Any help is appreciated.