I don't speak Ford, but I used to stress over this quite a bit. I have RVd with literally every type of RV, all with a gas engine. My current truck is our first diesel.
I was a diesel tech, and run a truck shop, so I just didn't want to hear or smell them after I got away from work.
The gas engines do fine, but as you know, the transmissions get a work out, and the mileage sucks.
If money is not an issue, get the diesel. It is certainly more relaxing at the end of the day, especially if mountain highway travel is involved!
Good luck!