Fred's advice above is good.
The 'dry weight' a camper is advertised at can often be optimistically low. It probably also excludes the weight of batteries and propane cylinders, plus typically any accessories the original owner ordered with the camper or added afterwards as well as the things Fred mentioned - all adds up to a lot of extra weight. Remember there is also the weight of you, family, gasoline, tools, etc.
People are typically shocked to realise: 1) These campers weigh that much? and 2) Is that all my truck is rated to carry?
Steve.