Hello and welcome. Not sure about the fuel mileage but the general rule of rving is to ignore the crappy fuel mileage. .
Yup - that's what I do when towing. I am much happier at the end of the day if I just consider the fuel part of the vacation cost and don't calculate the MPG. That said I notice that I get substantially better mileage if I use fuel that has no ethanol
__________________ “You have brains in your head. You have feet in your shoes. You can steer yourself any direction you choose.” -- Dr. Seuss
Yeah I add in the tanks of fuel as part of my trip. I know my local campground where I have a membership will cost me about 3/4 tank round trip. I know the state park nearest me is about the same. I know I will spend a ton hauling down to disney this summer but I also know that the price of the campground plus price of food plus price of fuel round trip will still be less than renting a room, eating out and driving in the smaller car or flying.