OK friends. I've read fuel mileage for a 35' gasser with the v-10 Ford engine pulling a 3500 lbs toad will be anywhere from 4 to 9 mpg. This is average traveling, not all level and not all hills. ...
My Monaco with a 8.3 Cummins averaged 9.5 round trip to West Palm beach and back towing a car on a Featherlite trailer. I drive around 65 most of the time.