Your towing capacity is determined by several factors, Engine size and Torque, Transmission, the Gear Ratio of your rear differential and the load capacity of your truck (primarily the spring package the manufacturer installed on your vehicle).

Whichever of these factors is the weakest will determine your towing capacity. Sometimes, you can increase the towing capacity by "beefing up" the weakest link, i.e..: adding an extra leaf spring would increase your "tongue weight" limit, or replacing your differential with one that has a  higher ratio could increase your "pulling weight" limit.

Keeping the above in mind, do you have a "Receiver" type hitch on your GMC?

Or do you only have a "Bumper" hitch?

If you only have the "Bumper" hitch then check out U-haul (or any other Hitch shop) to investigate which "Class" of hitch can be installed on your specific truck.

The hitch shop will be able to tell you how much you can tow with the various "Classes" of hitches that fit your vehicle.

I would not even consider towing almost 2,000 lbs without a "Receiver" hitch. I have seen several bumpers which were bent from pulling a trailer that was way too heavy for the bumper hitch to handle.

Have you checked out your "Owner's Manual"? The towing capacity is usually listed in the Specifications section.

Also:

     Checkout the discussion regarding weights of Scamps elsewhere on this site (link below)

           http://www.scampcamper.com/forums/scamp-trailer-weights

As noted in the post above, a fully loaded 13' Scamp weighed in at 1,700 + lbs.

Let us know what you find out and how you chose to proceed.

Good Luck and Happy Scamping !!!