Dreenn, Tow ratings are normally derived from hauling flat bed trailers with bricks or cinder blocks loaded on them. Height is kept below the top of the tow vehicle's tailgate, so wind resistance is not an issue. RV trailers have a great deal of wind resistance. This is why many will say to stay three or more thousand pounds under the maximum tow rating when towing an RV trailer. Best bet is to weigh your truck with a full tank of fuel, entire family, and everything in it that you would take on a trip. Minus that weight from the trucks GVW, and that is what you have left for trailer tongue weight. Personally, I would look at the max GVW of the trailer, and assume that it will eventually be loaded to that amount at some point in time, and make sure that weight will not exceed the ratings of your truck.