You've got to get off that "tow capacity" thing. Tow capacity is the most bogus, misquoted number on a pickup truck.
Misquoted, because most of the time people look at that "up to XXXXlbs towing" in the glossy brochure, and assume that their truck is capable of that. That "up to" number is based on a very specific truck engine/transmission/gearing/cab/suspension configuration, which almost certainly does NOT apply to the truck you are looking at. It is a maximum theoretical capacity under ideal conditions.
What's more important is the payload of the truck. Basically, the truck can tow about 7 times its remaining payload capacity, after you've installed any aftermarket customizations, put all your stuff in it, loaded the wife/kids/dogs and their stuff in it.
With an '01 GM 1500, that's not much. Those trucks typically have about 1200lbs of payload capacity, totally empty. You're thinking, "Oh, I can tow 8400lbs of trailer, awesome!" Not so fast... Throw a fiberglass topper on there, 350lbs of driver/passenger(s), and you've just reduced that by 1/2.
My method doesn't even take into account towing performance. That's just keeping the trailer tongue off the ground and keeping it under control on the road.