I'm trying to get a handle on how heavy of a camper I can haul. My 2001 Quad cab with fuel, my wife, and dogs weighs 7300 pounds. With a 100 pound tongue weight for my boat and 200 pound of gear for camping (minimum). The total weight of 7600 pounds subtracted from GVWR of 8800 pounds only leaves room for a 1200 pound camper! Is this the proper way to figure this?