truck selection/modifications for offroad popup truck/camper

By the way I am driving a 2011 GM 2500HD shortbed extended cab Duramax diesel pickup.

For offroading and handling a light load like a 3,000 lb. camper there is not benefit to a diesel engine. The extra power you do not need and offroad I worry about both range per tankful of fuel and how easy it is to find a gas station that is open. With diesel found only at about 20% of gas stations it definitely affects route planning.

The extra cost of diesel is $9,000 for the engine and Allison transmission. It also adds about 800 lbs. of additional weight and offroad lighter is better. I would go with the GM 2500/3500 as with the 2011 and later model years the frame is the strongest and stiffest you can get. The independent front suspension also makes the ride tolerable and is much better than a solid front axle on rough surfaces.

GM has a tow package that is useful even if not towing. The tow haul mode is great with a 3,000-4,000 lb. load in the truck (passengers, gear, water, and camper).

With any camper I would take the published weight and add 1500 lbs. to find the worst case load that the truck will be carrying. With GM trucks the 1-ton's can handle a payload up to 6,000 lbs. depending upon the configuration. The payload capacity from the manufacturer decreases based on the expected passenger load. A crew cab to that holds a driver and 5 passengers will show a reduction in the payload of 4 x 150 lbs. or 600 lbs. compared to a regular cab pickup.

For offroad I like as short a wheelbase as possible and went with the short bed truck with an extended cab. At the other extreme is a long bed and crew cab truck where turning radius is almost an oxymoron.

The Z71 "offroad" truck models often have 20" rims and tires and a greatly reduced payload capacity. Get the 18" forged aluminum wheels and you will have a greater payload with the factory tires and more options when you decide to replace them.

I am certainly not as experienced as some on the forum but here are a few observations . A crew cab with a 10 ft bed is going to be one long truck and if the camper is set to the back it will have the COG in back of the axle . If you really want that set up look into a cab/chassis with a longer wheel base . There are some other advantages to a c/c . The rear rails are narrower and standard for after market beds . They usually come with heavier suspension than pickup models . On a dually the rear axle is 4" narrower than the pickup . By removing the front wheel spacers you have the same axle widths front and rear as a SRW truck and can use aftermarket wheels and tires ( converting to singles).DRW cab/chassis usually come with a second fuel tank . Keep in mind approach and departure angles . Good luck

If you have a few days spare time read through this:

Alaskan Build-up

They did everything you were asking about ( and more)...

Ron,
Form follows function here. BE SURE the Alaskan weighs what you think it does. You don't want a big surprise when you drop it on your aluminum tray. The ones I know of are heavy suckers.
If you're going to replace the bed anyway, why not think about a C & C as an option?
My rule of thumb is to buy a lot more truck than you think you need for X camper. There are probably hundreds reading this that found this out the hard and expensive way. "Hey, my Ford .5 t. has a 9" rear end. Doesn't that make it good enough to haul that 10 foot camper?" You might peruse the 2013 Overland Expo posts of late. There are quite a few 'trail ready' rigs in there that might get you moving in the right direction.
For the last 12 years I have been trying out different techniques to make a Lance hardside last off-road, and not pull itself apart in the process. So far, so good. But, take that for what it's worth. For every one of me there are at least a thousand that will que up to be nay-sayers.
The good news is that you are coming from a 'Jeep' mentality, and already have off-road chops. However, that can be a liability which will become evident when things start to go south, grinding up that rocky arroyo. Also, your best chance of success is with a pop-top.
I came from a 4WD mentality, and built up many versions of camiones de doble tracion. My first rig, an SOA (an acronym I coined in an internet article in 1996) was on a 1949 Willys Ute Wagon, replete with Chevy V-8, Studebaker Overdrive, 5.38:1 gears, 7.50-16 tires on combat rims, Dana 18, T-15. Since the rig was originally built with a 4-banger, 60 HP, Go-Devil engine, the V-8 absolutely tore every other drivetrain part apart, one by one. All four axle shafts at least once, front and rear RG&P, steering parts, drive shafts, over and over, ball joints, trans, t-case (a couple times) overdrive (3 times) springs pads torn off, spring hangers ripped from the frame...all because the engine had too much power for the drive train. Well, maybe the fact that I was young and stupid did add some to the mix. My guess is we make our own mistakes and learn our lessons the hard way. Just keep your eye on the end result along the way and remember you are carrying all the weight of the camper not towing it.
regards, as always, jefe

While the Cummins is a great engine the early mechanical ones were loud for sure. The Duramax has always been probably the most quiet, civilized diesel of the 3. Fords 6.0 and 6.4 I would avoid. The new 6.7 seems to be a winner.
You're on the right track with the 3500 truck. Anything less doesn't make sense for a TC. With a SRW you may need to look into 19.5" rims and tires to support the weight. They don't work as well for airing down, however.
My preference would be for a GM truck. I've had nothing but excellent service from my Chevys. My work truck is an '03 F-350 and everything from the engine to the seat belt just doesn't seem as good. But, it does get the job done; usually.

The Duramax/Allison combo is hard to beat. One of the downsides for off-roading is the location of the DEF tank on the 2011+ models which can be mitigated with an after market guard. The Duramax is definitely quieter than the other options.