Decooney Wayne Safety wise you are better with a cab and a half pickup truck with a trailer towing package. Min gearing is 3.73. The better ones are 4.10 or 4.11. Get the 5.3 motor. The 6.0 will pull easier but not sure what the price differents is. I have replaced or repaired many 4L60e and 4L65E trans missions in the Envoy and TrailBlazer. The gearing is TOO low in them and they burn up the trans even in towing mode. The other big question is SPEED???
How fast are you trying to pull your rig? I have a dually with a 350 mouse motor and 4.10 gears. The trailer is 1,900 pounds and the car is 2,705. Add another 600 lbs for tools, spare trans and rearend. I pull in the mountains and get about 10-12 mpg on the flat areas I get 12-14 mpg. This is between 65-70 mph. Truck empty get 14-15 everyday driving. You could buy a short wheel pickup with cab and a half in a 1500 series For a good price. The 2500 series will have a better drivetrain and cut the MPG buy about 2 miles per gallon. Rick L. I work for GMC and Chevy at this time and for the last 11 years.