I went with a gas engine motorhome back in 1997, and am very happy with the results. It will out-pull most DP's on a mountain grade because the overall weight is only around 16,500 for the RV and another 3,500 for the car that I pull behind it. The HP/weight ratio is pretty good on a gas motorhome.
Oil changes are a LOT cheaper!
No fumes stuck to your hands after refueling.
Fuel filter was once in 20 years, around the 40,000 mile mark. Spark plugs on the new Fords are at 100,000 miles.
The 6.2L pulls great. I would suggest getting the 3.73 or 4.10 rear axle ratio. If you want the engine to scream at 55 MPH, then use a lower gear, not lower rear end ratio! It will allow much better mileage while not towing.
Like you said, in 5-8 years, you will want to upgrade, well before paying off the extra cost of that diesel engine.
The gas truck will be a little lighter, so more ability to tow with!
The 6.2L owned by many pulls a trailer great! So will the diesel 6.7L. Still it is nice to save $10,000 on the upfront purchase!
Good luck,
Fred.
