28' Chateau Sport weighs in at 11,500 and average about 9.5mpg. Last summer took a 5700+ mile trip to 13 Western States and averaged 9.78 (no towing) through the Rockies 2x and 2 days of head winds in Kansas. Also ran the generator for at least 1/2 the time we were driving and dash air. Hit 95+ degree weather for 3 weeks. The big factor is speed and terrain. I don't usually drive over 60 and now I don't look at MPG. I just enjoy the trip.