Depending on the size of your truck, the load you will carry and driving conditions, a half-ton pick-up will vary from 16-18 MPG highway, unloaded; 10-12 MPG (maybe 12-14 MPG) loaded, less with stop-and-go driving. Towing a trailer will add to fuel consumption, but not a great amount. Rear axle gear ratio will affect fuel consumption, also. A larger truck, 1½ ton or larger with a single-speed drive axle will get you 5-7 MPG empty or loaded, fast or slow, up-hill or down-hill. It sounds like you are considering pretty expensive proposition. I would plan for the higher fuel consumption, then maybe you will be pleasantly surprised.
Harvester
