I towed 6000 miles last October with a Coachman 31.5-foot, E-350, V-10. Over the rockies and all.
Trailer was a Pace 20-foot enclosed bearing a stock TR4. Estimate 5500 pounds.
The biggest problem is the motorhome overhang. Vehicle stability? Nope. There is no aero drag on the trailer. Usaully can't do more than 50 MPH without getting an uneasy feeling. Find a ToterHome with a short tail.
Averaged 7 MPG.
Tow the same trailer with a heavier car (Stag) behind my 3/4-ton 8.1 Suburban. Truck knows the trailer is there, but it doesn't care. Solid, straight, stable. Mileage only a little better, but I'm towing the speed limit, 65 or 70 with no problems.
Phile, DId you reinforce your frame rails?
DHardison, thanks for the reply. Glad to hear from someone with a similar setup. I plan on reinforcing the frame rails on my rig.
Also I forgot to add I do have rear airbags, Im hoping they will at least make it more stable.