ProMaster wrote:
Pluses - Good gas mileage (getting around 13 mpg including frequent trips into the Blue Ridge mountains),
Hmmmm .... IMHO, 13 MPG is not that much of an improvement - to be worth what one give's up with that chassis - over what fuel mileage many get with their Ford E350 or Chevy 3500 cutaway van based small Class C motorhomes.
What I'm most leery of when using that ProMaster chassis under a Class C is it's front wheel drive. It seems to me that with that chassis it would be real easy to unknowingly change the front/rear wheels weight distribution ratio - to a more rearward bias - by owners when they load up their rigs for trips .... which ultimately reduces the traction-to-weight-distribution relationship of the vehicle.
Even if owners do not cause this front/rear weight ratio shift when loading for a trip, having the lightest loaded wheels (the front ones) always being the drive wheels would make me uneasy should RV traction ever become even a slight issue on camping trips where every driving or campsite situation cannot be predicted ahead of time. I'm not talking about "getting away with a front wheel drive RV" most of the time in most of the world. I'm talking about making an RV buying choice upfront whereby one never gets stuck (no pun intended) with a traction situation that could have been avoided through purchase of an RV where the higher amount of it's weight is always on the powered wheels - the rear wheels.
(The above argument does not apply to a selectable drive four wheel drive RV whereby the default travel mode is FWD and RWD can be added by the driver whenever needed.)