I'm not sure if this point has been brought up yet, but it seems like many times people seem to think 3/4 ton is synonymous with diesels.. As a few guys have pointed out, the large diesel engines in today's HD trucks are often WAY overpowered for a simple popup camper and a small boat or similar setup..
A new diesel is expensive, and very heavy.
When I bought my Silverado 2500HD new in 2005, I considered the Duramax and Allison option. For the $8k+ extra it would have cost me, I would have had to drive over 300k miles before BREAKING EVEN with the fuel savings.
Combined with the extra 800-1000lbs in weight for the larger motor and transmission and extra cost, I decided the D-max just wasn't something I needed. I do pull heavy 10k lbs+, but only a couple times/year. I can live with 6mpg a time or two/year for the simplicity, and weight/cost savings of my smallblock over the diesel.
Today's trucks have A LOT of power. My 6.0L is the smallest option even available in my truck and even loaded or with a heavy trailer it keeps up with traffic, even over mountain passes. Doesn't have the grin-inducing power of the diesels, for sure, but plenty of go for what I need it to do.
In our situation, where GVRW takes importance over power, going gas in an HD truck can be a good option. My truck has a 9200lb GVRW, but only weighs about 6200 with my larger tires, bumper, winch, and toolbox/tools. It's only a reg cab, so comes out pretty light for a big truck.
Not sure about the other brands out there, but most of the suspension, brakes, and steering components in my truck are identical to what would be found under a quad cab Duramax, but are basically doing the work a 1/2 ton could do most of the time. I just pulled my front brakes yesterday. Still 1/2 of the original pads left at over 160k miles..
I've ordered a Grandby from FWC that should be ready mid-December. The plan is to build a custom bed for the truck, load the camper up, and head south to Argentina next year. I'm estimating I'll be at about 8500lbs loaded for the trip, which puts me 700lbs below GVWR. Not a lot of overlanders out there UNDER GVRW. I bet there are guys running 4-runners that come in near there.
I'm a big believer in being over-prepared and under-loaded. Most of the failures I see out on the road are due to chronic over-loading. Wheel bearings, steering components, etc.
I'm not knocking diesels, or 1/2 ton trucks at all. In farming and construction, diesels definitely have their place. If you don't mind the extra weight, complexity, and cost, but really love the effortless "pull" a big Cummins has, by all means get one. They are awesome.
I just have had good luck with the HD gas I have, and see a lot of guys discussing either- a 1/2 ton gas, or a HD diesel and wanted to highlight a third option.
Cheers,
KP