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. ...
I drive the Ford V-10 motorhome shown in my sig, towing the Jeep shown in my sig. I keep a log book where I enter every gallon of gas that is put in the tank, what date I bought it, how much it cost, and the odometer reading. I have never computed the MPG, because I just don't care! I know it is terrible, and I know it is to be expected. Worrying about fuel economy in a motorhome is an exercise in futility. It is terrible, and there is very little that can be done to improve it!