I'm a bit surprised that you eliminate quads based on their range. I can generally get 60 miles on one tank, more if I stay out of 4WD and avoid full-throttle, and it's an easy matter to strap a gas can or two to the rack. I have a rear cargo bag that incorporates an extra seat in case I need to haul a passenger. If it becomes impossible to shelter-in-place and the condition of the roads are such that I can't take my full-size rig (a Dodge 2500 V10 w/ shell), then you can bet we're taking the ATV's.

Regards, Vince