Margaret, look at the tires on the truck and make an informed decision there too. My F150 came with Michellin tires.. I thought it was great that I had a good brand of tires.. only issue is they are P series tires with a recommended inflation of 35lbs per sticker. They have lasted well and ride super when not towing; however, they feel a bit squirmy in the rear when I am towing, especially on interstate highways. I have determined that adding extra air, up to about 44-45 lbs makes a huge difference to towing my TT. I have a 28ft with a dry weight of 5200. I will be buying new tires within the next few months and will change to some tire that has a stiffer sidewall. I know it will make the daily ride a bit stiffer, but it will make me feel safer towing.
The whole point is as you look at trucks, don't forget to look at tires.. When I bought this truck I was so busy looking at weights, tires didn't even get considered.