We have owned a 25 foot Class C, a 30 foot Class A and a 33 Foot Class A and now we are back to a 26 foot Class C. I can tell you, the gas mileage is virtually no different in any of them. We get 7.5 to 9.5 and it all depends on wind, hills and speed. Everyone thinks that a small Class C gets better, but we have found they are all the same. All of our units have had the Ford V10. We went back to a small class C for the ease of maneuvering. Driving small or large on the highway makes no difference. Make sure you go with a bed down, even if it is a corner unit, you will not regret it.