GVWR includes everything the truck's tires will carry, including passengers, gear, and the tongue weight of the trailer. The tow rating is different from GVWR. Assuming the truck weighs 6K, (my 01 XLT 4x4 is about 5700) that leaves you about 1300 lbs of cargo capacity. Assuming a tongue weight of 500 lbs, you can still put 800 lbs of cargo in the rig. Not sure what the tow rating is on that rig, but you're gonna be pushing it with that trailer.
Dry trailer weight usually DOES NOT INCLUDE things like appliances, AC units, etc. You actually need to weigh the trailer. My 19' Superlite is listed at around 3000 dry, but loaded with 900 lbs of quads, scales at 6000, and my truck hates it. Also, you're going to want a load distributing hitch to take up some of the sag. Good luck