Soooo many factors in MPG. How you are loaded, wind, terrain, weight of the MH, the engine, etc etc. Gassers will get anywhere from 6-10. Some of the new short DP's can get double digits and FREDs (Front engine diesels) or B plus can get 20 or more. You would have to set your sites on a specific model and year coach to get anything close to an accurate estimate in MPG. Even then, all the factors can change it drastically. BTW your MPG seems really low. I would expect 8+ in your current rig.