Being successful at trailer camping involves having a capable tow vehicle. The vehicle itself has to be able to handle the additional stress of the trailer and be able to safely stop the additional load that the trailer adds to the car, truck or van. Your vehicle owners’ manual will determine what trailer weight is allowable to pull with your tow vehicle.
You manual will have the following numbers:
Gross Vehicle Weight Rating (GVWR). Amount the tow vehicle may weigh when fully loaded including the tongue weight of the trailer
Gross Combination Weight Rating (GCWR). Weight a vehicle can tow. This figure may vary depending on the vehicle’s equipment, such as a manual or automatic transmission and whether it is equipped with four-wheel drive. Permissible combined weight of the tow vehicle, trailer, passengers, equipment, fuel, etc., that the vehicle can handle,
Gross Axle Weight Rating (GAWR). Weight a single axle can carry, which influences the allowable tongue weight, and the weight distribution of whatever you load in the vehicle.
The National Highway Transportation Safety Administration has a good online pamphlet http://www.nhtsa.dot.gov/cars/problems/equipment/towing/index.htm about towing.