All good advice above. I'll just add that our class C with the V10 averages 9.6 mpg. I usually drive 55-60.
You mentioned that the RV is plugged in when in the driveway. Some converters, which convert 120 volt AC to 12 volt DC, have too high a "float" voltage output for continuous battery charging and can boil the water out of the house batteries. If you are plugged in at home all the time, it would be a good idea to keep an eye on the water level in the batteries on a monthly basis and top them off with distilled water as needed. If you find after a few months that the batteries don't need water added, you probably have one of the newer converters that don't have this issue.