I towed my 31' Excella with my 2000 Silverado 5.3L w/tow package on several 700 mile each way trips from NC to Florida without any problems. However, when I tried the Blue Ridge Parkway the brakes got hot going downhill. The engine was barely sufficent and the transmision overheated going up. And I was geared lower at 3.73. If you stay in the flat lands you should be ok with the 1500
. I suggest not going to the high hills if you use the 5.3L gas 1500
Silverado. If I remember the max tow capacity was just over 7,000 lbs.
I have used a 2500 Duramax. It will definitely do the pulling job, but you should look at some of the threads in this forum about tow vehicles that are too heavily sprung and cause damage to the structural elements of trailers.
I now tow with a 2010 Silverado 5.3L gas 3.42 rear end with a six speed trans. It will take my 25' Safari over the Appalachians with ease.
Hope this helps!