Obviously you'll have plenty of truck/1 ton to tow that 5th Wheel set up.
It is totally personal preference in truck brands when it comes to diesels...as they all are so close in power/torque output-you can't go wrong with anyone of them IMO.
I currently love my F150 Ecoboost for towing, but wouldn't hesitate to move up to a diesel if I decided to go 5th Wheel.
My first choice would be Ford, only because I like the trucks setup.
Happy camping!
