Have had some experience camping longer term...
* avoid tents and pop-ups made of fabric...at times you will be in windy areas...strong winds will tear up a tent or pop-up in a week at least....
* try not to use an expensive vehicle or setup....might avoid vandalism
* while mpg is important...having useable room and no need to setup and tear down a popup or tent in invaluable.
* the only trailer I'd use would be small and fiberglass...last thing you want out in the boonies is alum or fabric.
* I'd go with the Ford Transit Connect sans box on top...you have some room. You could put in an inexpensive bed platform with storage underneath. 2WD...but you can get around most places without 4WD.
* there are some yahoo groups that focus on living in vans, etc....great for ideas on refrigeration...where to camp...how to fix one up, etc.
* If you stay out long enough...you won't return as the same person. The aliens will get you and put in an implant.....