We got back from a 5700+ mile vacation drive from Texas to Georgia, to Rhode Island, to Maine, New Hampshire and Vermont. I kept track of the fuel we used and we were very pleased with averaging over ...
To OP, we have a 2005 Leisure Travel FreeSpirit Class B that is built on the Sprinter chassis with the 5 cylinder turbo charged engine. I have fuel records for all 149647 miles we have put on it and our average mileage is 20.18 MPG. Not bad considering the roads traveled including many mountains.