I've given this issue a little thought and I think a good solution is a small dual sport bike (mine is a Yamaha TW 200). It is capable of carring some gear, going off-road, or travelling most roads.While full speed interstate travel would be unpleasant with this bike, it is small and light enough to cary on a hitch mounted dirt bike carrier. This makes it possible to have two vehicles without a trailer. I use mine to avoid towing a car behind an RV, but it would server well in an emergency. The bike gets 70+ miles per gallon (with a two gallon tank) and will handle some very rough terrain. I can even share fuel with my triple fuel stove using my camping fuel bottles as an extra reserve.

Marcy

I want one of these!
http://www.terracarry.com/9600series.htm

Very cool indeed !

No kidding, very cool ! I want one too !!!

Something like this is a cheap / reliable / easy to maintain option:

Ducati Condor 350

I don't understand why motorcycles don't get much better gas mileage. That Ducati, for example, has a 16 hp motor and gets 52 mpg, about the same as a Geo Metro that can carry 4 passengers and/or a lot more cargo, and has 5x the curb weight. What's the deal? The Honda Insight gets even better mileage (around 70 mpg) and with a 10.6 gallon tank, has around 700 miles range.

This is what I'm looking at

http://diesel-motorcycles.com/

enjoy
Brad