[MarkoPolo]

A quick follow up to address Love to Camp's comments.
I think your comments about an SUV or even a sedan with diesel are right on. My "other" car is a Volkswagon Tiguan and if it were available as a diesel in the US I would have jumped on that for sure.
But, the OP was asking about heavy duty pick ups. I priced a Ford F-250 as close as possible with the same options my F-150 has. So, first off you are looking at a 3/4 ton pick up vs. a 1/2 ton. The F-250 is a bigger, beefier truck with an inch or two more ground clearance. I think the frame itself is heavier duty as well. At any rate, it priced out nearly $5000 more than the F-150.
So, in pick ups at least, the HD is a more expensive way to go, unless you really need the extra tow power.
I started out much like Dave, trying to buy a tow vehicle that was "future proofed" as much as possible. I was wondering about fifth wheels and larger TT's, too. But after seeing the new Trailmanor 2922 and looking at a lot of 5th wheels and travel trailers, my wife and I realized that for the type of camping we really enjoy, ie; dry camping at forest service campgrounds and even some boon-docking, the larger trailers and 5th wheels just wouldn't work. So once we had the trailer decision made, it was easy to back down to a 1/2 ton F-150 with the Eco-boost engine. I kind of resisted that engine until I talked to two different mechanics I know that have worked at Ford dealerships and they both gave it a big thumbs up. I have read it has at least as much torgue and pulling ability as diesels of 10 years ago. The only penalty I see is the mileage is not as good as a diesel when towing, but as good as or better the rest of the time. The other big plus, is high altitude performance. We spend most of our time there, so the turbo really works in our favor vs. a non-turbo gas engine.
Sorry for the long winded post, but I thought that might clarify how I perceived the diesel vs gas issue.