I aways fall under the better safe than sorry. If you're going to spend a lot of time with it loaded and it's going to see a lot of miles, just get the 3/4 ton or 1 ton truck and enjoy the comfort and peace of mind that you are well within the load capacity. Even with a 1 ton, I could see you wanting to get larger bumpers for the overload springs and having them engage sooner for sway and sag. Possibly even airbags. I think once you have the camper, add water, fuel supplies and all of the other things, you're going to find yourself at, near or over the recommended load limit on a half ton.
Yes the stock suspension on any truck is a compromise but I feel it is more of a compromise on a half ton. The manufacturers are trying to make it ride smoothly empty and then be able to carry significant weight. Not great if you plan on being loaded down almost all the time. The stock setup isn't designed for that. Airbags will help but they don't make the truck anymore safe if you are over the legal limit for that truck.
If you're getting a "shell" pop up truck camper with no stove, no microwave, no toilet, no nothing, a half ton would be fine and would still need airbags or helper springs. If you want a fully loaded hard sided camper with creature comforts and the extra weight associated, I would suggest a 3/4 or 1 ton with either Timbrens or airbags to help keep the load steady. At the very least overload extensions on the overload leaves so they contact earlier and stay in contact longer.
If this is your DD, a half ton will obviously be more enjoyable to drive around, better ride quality, slightly smaller, better MPG but you need to really decide how heavy that camper will be and how much stuff you will bring to know if that truck will cut it.
Best of luck in your search.
-jorge