Truck Tire Capacity

Thanks for all of the suggestions. Although I don't have either the truck or camper yet, I have a pretty good idea of what they will both weight as I am getting the same setup that was featured in the Truck Camper Magazine's Payload Match article (fewer options on the camper, more options on the truck)which used CAT scale numbers. It appears from my research that the best I can do on the stock rims is to increase one size from LT 265/70R18 to LT 275/70R18 for an increase in capacity of 230 lbs in the rear. I don't expect to meet or exceed my factory rear axle rating (OEM tire capacity)of 7050 lbs, I am getting the snow plow prep which will give me lots of front axle capacity for a front hitch carrier and I shouldn't be over the GVWR by muchif at all. I was just looking for as much cushion as is reasonably available and wanted to make sure I wasn't overlooking some magical tire that would boost me even more.