With trucks of our vintage you will be arguably overloaded with even a pop-up truck camper. As configured with the stock tires at xx psi, rated payload in the bed is going to somewhere around 1800# and with fully loaded pop-up campers coming in at 2000# or more. If you decided to go 1 ton SRW...you actually only get a few hundred more in payload because the tires remained the same (higher pressure on the door jam?) and you would be OK with a pop-up truck camper.
With that said...because of the short bed expect to carry little to no weight on the front axle and maybe even lose some off the front axle...not a big deal considering the boat anchor of an engine we have. For your setup you will essentially carry all the weight on the rear axle...make sure you do something about your tires as they are the weakest link. Followed closely by the lack of overloads, so something like supersprings, timbrens, stableloads or airbags will likely be needed.
Good luck and have fun.