Tow ratings are of limited use, since they do not account for the wind resistance of your RV. A 10,000 lb tall rectangular box tows very differently than, say, a 10,000 lb boat, or a flat cargo trailer. The number you will bump up against first with most 1/2 ton trucks is your payload rating.
Another knock on 1/2 tons is some come stock with semi-soft suspensions and P-rated tires (plush ride), as well as low numerical rear end ratios (better fuel economy). None of these features are tow friendly. Bottom line, know your truck's capabilities. IMHO, that's a lot of trailer, and needs a lot of truck.