 The GVWR, minus the weight of the truck with passengers and fuel is the payload that the truck may legally carry.Stability can be improved by the addition of a sway bar, add-on overload springs or inflatable airbags on the rear suspension.Most campers are rated at their "dry weight" which is the weight of the camper less any fluids like freshwater or sewage, and any possessions or add-ons that may add to the total weight.