Here is an old idea that at first glance seems like a viable solution to high fuel prices: A fuel system that burns just about anything except rocks, glass, and broken cement. The fuel of preference for this type vehicle is wood and wood scraps, or cellulose.
You could also burn easily obtainable wood for your other power needs while boondocking out in the national forests.
During WWII wood burning vehicles were commonplace. These cars worked by gasifying wood and burning that directly (see photo of wood burning vehicles, courtesy Low-tech Magazine). Today we call this type of fuel “biofuel.” The process converts “biomass” into biodiesel. Burning wood or scraps also is thought by some to be carbon neutral.
Joost Conjin, who not only built a car out of wood, but toured Europe and made a movie about his trip, says, "You can go around the world with a saw and an axe."
However, when studying this fuel application, it becomes apparent that if the idea caught on we would soon deforest the planet, and carting around the fuel converter (like the modern version in the bed of a pick-up truck) would soon become as unwieldy as cooking inside your rig with a woodstove.
Though on the plus side, since it would take about ten minutes to preheat your rig to drive, chances are you would take your bike instead. And if you had to cut wood for three hours a day to make a trip, think of what good shape you would get yourself in.