My advise would be to first check your vehicles GVWR it is probably on a sticker on the inside of your door jamb.
GVWR varies based on options added to the truck. Once you establish the GVWR subtract the curb weight of your truck, a full tank of fuel, the weight of your passengers and any other items you might be carrying. After doing that simple math then you will know how much camper you can carry.
For example:
Assume the GVWR (gross vehicle weight rating) is 7,000 pounds.
The weight of the truck is 5,200 pounds, add two 200 pound passengers, add full tank of fuel 200 pounds, add cooler with food and ice 30 pounds, add fishing and camping gear 170 pounds. Total 6000 pounds. Subtract that total from the GVWR (7,000 - 6000) leaves you 1000 pounds max safe payload or max safe weight for the camper.
Looking at the link Rusty provided you can estimate an 8' NCO at 1500 pounds. The example above could not handle it. If you have 2000 or more pounds left over in your GVWR then it will work but, if you do not then no one wants to drive their truck for any length of time at or past max weight rating as it wears out the springs, the tires and the brakes, not to mention the transmission. Also operating past the max weight rating is not safe either.
Hope this helps.