Your post just reminded me of something. In some places in europe they still use two-wheeled tractors (while sitting on an open trailer attached to it) as a farm vehicle and for general transportation. I've seen those trailers loaded up with 5 or more people and full of supplies being pulled by a tiny two wheeled tractor. And these were very steep, unpaved mountain roads. They're slow but they can pull some serious weight. BOV of last resort maybe?