Yur actually considering putting a camper with a 9 foot floor length on a 6 foot bed?
Your name says it all. That camper is waaayyy too much for your 2500HD. You need to reconsider the purchase or at the very least upgrade to a dually. In stock form that truck, depending on cab and options had somewhere around 1800 pounds of real world payload capacity. BT,DT and have the scars to prove it. It is simply put not enough truck.
Never let the terms like "Dry" or "shipping" weights fool you. They are misleading at best and downright dangerous at worst. The only time you will ever see that number is in some engineers imagination. Add any options, some water, food, clothes to the camper and you will skyrocket in weights to far closer to GVWR than dry.