Essentially, your payload is what matters, not your towing capacity. You will always come up against the payload number before you reach the towing capacity. Your payload needs to exceed the tongue weight (take the trailer weight and add 25% for gear, the logic being that the bigger the trailer the more junk you will put in it. Then take 15% of that number as your tongue weight.) Then add the weight of any passengers, gear and anything else you might be putting in the bed. Add the weight of a weight distribution set-up, about 100 pounds. Whatever that works out to, your payload needs to be more. You'll have a tough time with a larger trailer not exceeding that number for a half ton pickup. Half tons do well with trailers about 24' or less.