I towed a 5,500 pound -29 foot travel trailer 8,000 miles in 8 months all around the U.S. w/my 2WD 2011 Silverado Crew Cab with the 5.3 and had absolutely zero issues.
The only time I wished for more power was coming home through Parley pass about 50 miles from home. But it was a great trip.
I have the 20" tires. Some on here will say 20" tires limit your LT tire choices should you decide to switch. But I say all you need are tires with a "XL" rating to be OK. I pulled the trailer to Florida and up the East coast with the stock (P rated) tires with no issues. I replaced them in New Hampshire due to them wearing out.
