Charlie,
You could go steam punk style and build a wood gassifier. Ton Carlisle used to be an instructor at our local comm college and he had convert a pick up to pull his boat to the gulf and back without using one drop of gasoline or fuel. He kept the bed stacked with wood and would start the burner and go have a beer, then get in and drive it and the boat home. It was hysterical to look at, but it did run on the wood vapor. A little low on giddy up but fast enough pulling a boat anyway, and you couldn't be in a hurry to leave, but it worked great.
Bob