My Volvo tractor has been seeing similar duty for the last year. I have less than $14,000 in the truck which includes all conversions needed to register it as a motorhome. We average 10. 5 MPG loaded with the pathetic lightweight of our 18,000 lb fifth wheel trailer.
Not only are nearly all the parts on my Volvo cheaper than my dodge for general maintenance, I can fit 6 people in it comfortably, put our quads on the bed in front of the gooseneck hitch, and pull over 33,000 lbs if needed (Limited only by the hitch I have on it, why I would ever need more, I don't know)
As soon as I figure out how post pics here, I'll put a few up to show.
My frame is enclosed with a 13 foot Rv hauler bed and RV fifth wheel hitch. The only downside I have with it is I spin alot when bobtailing and I get stopped by the DOT cops to check the registration status and sample my fuel. So far, all stops have been quick, courteous and non eventful.
If any of you guys want a really high power and also stoppable RV hauler, you will be very pleased with a used class 7 or 8 tractor. Just make sure you have maintenance records turned over with it. Hard to get even a dodge to take the abuse my Volvo does and still make it over 500,000 miles without falling apart.