Buying a tow vehicle question

Thanks to all who has responded. Last year I bought a 2015 f250 4wd to tow a 5500 dry weight tt. 3.73 axle. 6.2 gas burner. Haven’t pulled it anywhere much since I bought them both. Lived in the camper while waiting to get in a new house. Pulling it home on the interstate in hills and trying to keep speed about 65, the rpms were very high and I was concerned. Also, dropped to 7 mpg as long as I was in hills but mpg isn’t a major factor. Performance on the road is more important. Downsizing for traveling and want to make the right choice.