What might the towing capacity of a 2003 GMC Envoy be? According to GM, the total towing rating is 6300 lbs. It has a 113" wheelbase, 4:10 rear end, locking differential, & load leveling suspension. We are looking at a 27' Kodiak (4780 lbs dry weight). Would this work and any ideas on mileage? An equalizer hitch with anti-sway bars & brake controller would be purchased. Transmission cooler would be installed. This trailer would be used for trips 2000 miles plus.

PLEASE, forget dry weight, forget shipping weight. The only number you are interested in is the trailers GVWR. To answer your question, you will not be happy towing much over a tent trailer with the I6 Trailblazer/Envoy/Bravada class of vehicle. I had a 2002 Trailblazer and made one trip before I traded out of it and bought a Tahoe to tow my 20food TT.

Donn is right ya'know.
Play with this towing calculator, designed by Ken Lenger, to safely and accurately match a trailer to your vehicle.

Keep in mind that the 'towing capacity' of a truck is usually with no accessories in the truck, no cargo, no passangers. Just a 150 pound driver and a bit of gas.

So, unless you truck is not loaded like most of ours are, your true towing capacity is probably significantly less than 6300 pounds.

As is said, you'll never pull an empty trailer (except possibly to get it home) so using dry weight to match your trailer and your tow vehicle will almost always get you in trouble.

JerryC, welcome to iRV2.

The previous posters have given you excellent advice.

It is always safer, less stressful, and more comfortable to have too much truck, rather than one that's barely capable.