Here's my choices:

1. 650-class dual purpose motorcycle. (Kawasaki KLR650, etc.). Best for maneuverability. Good range (big gas tank). Legal on highways.

2. Jeep Wrangler (pick your vintage, long wheelbase is better--CJ-6/CJ-8/AEV 112). Best 4WD for maneuverability. Can carry a goodly amount of stuff. Probably best for two people max.

3. Full-size 4WD pickup or van. Best for carrying lots of stuff, but not great for off-road (or on-road!) maneuverability. Can carry the bike. Available with diesel engine.

My favorite scenario is the pickup at the destination, and the Jeep and bike at the home (assuming you have a place to go!). Wife drives the Jeep with the kids and supplies in back and I ride the bike as advance scout.

Am I getting too paranoid? <img src="images/graemlins/smile.gif" alt="" />

In reality, any well-maintained vehicle that has at least *some* off-road capability is sufficient. Base your needs on how much cargo capacity you need for your family.