When I had to replace my Expedition El this summer after it was totaled (not my fault, and it was paid for) we had just sold our X19H with plans to go a little bigger with a TT vs Hybrid, prior to the need to replace it I was limited on how much larger we could go on a camper. The Expediton towed well but I was worried how it would do with an extra 2000+ lbs although it was rated for 9,000 on paper but not real world.
I loved my EL as it had a ton of room in the back which I used even when not camping, a Truck really would do me no good unless I put a Bed Cap on it and if I got a truck I believed I should get a 3/4 and if a 1/2 ton was the only option I might as well stay with an Expedition EL. I did not want or need a Diesel as they are not like the ol 7.3's from the old days, to much stuff to go wrong and big $ to fix, my BIL learned this, but he needs one for his work. So I thought a 3/4 was out of the question and almost settled for another used Expedition which would have been paid in full again.
Somehow I ran across the 6.2L section on the Ford Trucks Forum (I wanted another Ford product) and found out that the Gas engines held there own for any towing I would ever do and that the Tranny was the same one they bolted to the Diesel as well as the rest of the Truck was the same mechanically.
So I did more research and read all the forums I could and watched all the towing videos I could find and decided that was the route I needed to go. I never thought I would ever have the opportunity to get an F250 but although I have not had the chance to tow with it yet I have put 7,000 miles on it so far and am so happy I got it. We were out again today looking at campers and it was so nice not to have to worry about being able to handle any of the Jayco's we were looking at, the largest being 28BHBE down to a 24MBH Whitehawk. Just because I got a big truck does not mean I want to overdo it, feels good that I have a lot of truck left with less worry on if I even had enough.
I had told myself if I did ever get a F250 I would get a New one and optioned how I wanted it, so I did buy New which hurt $$ and I did put an ARE Z Series Cap on it with Bed Rug which hurt $$ even more but now I got the right truck for hopefully a long time, even though I did have to finance some. It is a tough decision to go from paid for to not paid for, it will be 10 yrs old when my son is 19 and his first truck (that's how I sold myself on it
Moral is the Gas engines in any brand of 3/4" are a good choice and allows you to stay in the 75% range of the trucks capacity which is equal to a 1/2 tons capacity. Remember it's not so much the Engine but all the other mechanicals that are so much stronger and heavier.
On a side note I drive 114 miles a day, 110 is highway, for work and have been averaging 15.5 mpg keeping around 65mph on Cruise, my Expy averaged 19. Expy was 2WD, F250 is 4WD. It does not get EcoBoost mileage but I also don't have to ever worry about blowing up a Turbo or 2.
Don't be afraid to get a Gas 3/4... Good Luck with your decision, as you can see I have been there.