I trucked all over on and offroad with a 4WD Toyota mini-truck carrying a Six-Pack camper. The combination worked great for many years. I would trust a Toyota half-ton truck over any made by the big 3, especialling offroad.
The payload in the bed is primarily limited by the tires' load capacity at the rear axle. There is going to be a maximum load range that they can carry. Secondary concerns are the shocks and leaf springs and even 3/4 and 1-ton truck owners end up augmenting the stock springs, shocks, and replacing the stock tires before heading down the highway with their new camper.
The heavier the camper the less you can carry in passenger, gear, fresh water, and other items so get the lightest camper that will still work. The smaller campers forgo a shower and most will have a cassette toilet. Holding tanks for fresh water and gray water will be smaller which can be restrictive. Some do not have a house battery and that is not good. You do not want to have the camper draining the starter battery for the truck.
The camper forums for offroad use will provide a great deal of information that is applicable to 1/2 ton trucks. This forum is 99% comprised of people with large heavy duty and very heavy trucks with large and super large campers. Lots of good information in these areas but not a good source of information for anyone with a 1/2 ton truck.