I wouldn't assume a 1/2 ton is sufficient. Some of the newer ones with high payload packages and low axle gear ratios will be fine; others will not. Although others here might suggest you will be fine with a 6 cylinder engine, I would strongly recommend against that no matter what any salesman, marketing document, or review online states. Get at least a small V8.
Make sure you have at least 1000 pounds of payload leftover after you subtract the curb weight from the GVWR and also the weight of any passengers or other equipment you're going to have in the truck itself. Personally I think that buying a 1/2 ton truck with the intention of trailering is a poor idea, but as long as you keep the weight and size modest, it doesn't present a serious problem.