I ride ( a lot!) and have riden for many years. My larger bikes (1000cc and up) get about 45 mpg. The mid range bikes (350cc to 1000cc) get a little better mileage but the tanks get smaller quicker. The small bikes get incredible mileage but tend to have very small tanks...for this forum, a 150cc to 250cc bike (dual sport type) fitted with a baja style tank (available aftermarket) gets the rider through many areas, is streetable and gives 200+ mile range. Also the paris/dakar style and GS (BMW) style bikes are outstanding for light off road/single trak trails. I think having a small bike and a mid range would be a good idea for "preparedness".