Check the tires you want and verify that the minimum width they require works with your existing rims. With my 17" tires all the ones rated at 3750 or more required 7.5" wide rims at a minimum and the prefered width is 8 inches. Going narrower is a way to end up with split rims and tire failure. I can't see taking the risk when carrying a heavy camper on the highway.
Difficult to determine load capacity of GM rims as they have used so many. Even now the 2014 2500HD/3500HD can have any one of 5 different rims provided.
All the manufacturers put a payload sticker amount based on how the truck was configured the day it left the factory and the key variables are the leaf springs and the tires, both of which can be changed without affecting the safe use of the truck.
The forged aluminum wheels are the strongest and with a 2500HD I would get a set of used 18" rims from a 3500HD. Lots of guys take off the stock rims to get something prettier - go figure, but it means that you can find them for $50 a rim on craigslist. Verify the bolt pattern as it changed in 2011.
