More thoughts, for those that are serious about a van...size matters. Long and tall is attractive, until you come off the highway into an urban setting, and want to park somewhere. My standard length Chev will clear parking garages, Sonics , assorted drive throughs, etc, albeit with some puckering up. A longer van would present problems with most urban parking spaces.
Too, weight, mileage, and ride become factors. The longer body vans are 3/4 ton models, with heavier everything, larger engines, harsher rides, and lower mileage.
There are some shorter, older vans out there with short wheelbases that are about the size of a pickup with a camper shell...hanging in one of them, while probably doable, would be less than ideal.
As for 4wd, Chev offers an awd option for their van. I passed, opting instead for what they describe as a locking differential. That may have been a mistake, as performance off road is still only fair, and doesn't inspire much confidence.