Thanks for chiming in guys.
For the build I have in mind I would like to remove the bed permanently and diy a flatbed type caper that overhangs over the cab for sleeping quarter. Maybe pop top style to save mpgs. Spartan, low tech, no batteries, no solar, maybe a propane heater and cook top and 12v yeti fridge.
A traveling rig rather than a boodocking rig.
For me? Heck no. Go 250/2500+ now or regret it later. Can't tell what you're building though, or where you're going. But for me I'd start with a bigger truck. Even if your camper is just 1100#, that's still much easier to haul with a 250.
I hated half tons and Tacos with mini campers. What's the point of a camper that is no more plush than a RTT? At least RTT's get a fresh breeze and have almost no effect on the trucks handling. To keep the weight down, the camper was as spartan as a tent. But it was still heavy enough to wreck the trucks off road capability down to what a heavy 1 ton truck with a light, but larger camper does.
You'll have more weight wiggle room to design something nice. You can even have a battery! Lol. If you're going fullsize and camper, you don't lose anything by starting with a stronger heavier truck.
What exactly, weight range are you thinking of with your camper? Multiply that by 2. Then find a truck with that for cargo capacity.
I don't recall any frame issues with any of our American trucks. Springs, brakes, tires, and level ride height, on the other hand...... IME, pop top FWC's get about the same mileage as hardsides, assuming that it's a narrow hardside of the same width as the FWC.