I have the CDL in the family, I do most/all of the driving. We had a 04 32' v10 with the 4 speed, never towed anything, its our weekend get out of town vehicle.
It depends on the conditions, the F53 chassis is often all over the road with a good wind, with hills the v10 is screaming as it drops gears for more power, even in the tow haul mode. After adding $4000 in "handling improvements" we were able to do the speed limit most of the time, though it was still a white knuckle experience. We saw low of 4.5 mpg with a 25 mph head wind to 8 mpg on a near perfect day with few hills. If we ran the genny for A/C on those 85 degree days our mpg dropped .5 miles per gallon so from 7 to 6.5.
The upside was the v10 always started, got us to where we needed, and was cheap to maintain, absolutely no issues.
However, for work I drive diesels, so we traded the 2014 V10 in for a 2007 40' with the small but mighty 5.9 Cummins diesel, no more white knuckle driving, and we see 8 to 10 mpg.
There's no perfect motorhome out there, just figure out what you and family need to be happy, and then enjoy it.
My truck only gets 13 mpg, it has no queen bed, shower, bath, refrigerator, stove, tv, recliners or couch. Put it in perspective, basically you're driving a house. You want mpg's you drive a tiny little car, that is only for driving not living in.
Have fun in your search for your home on wheels.
