Get the biggest truck 1/2, 3/4, 1/1 ton you can possibly afford. Dually if you really want good stability, but also costs more. Brand, pick your choice. They are all good.
I drive a 3500 dually. We got it 1 year used. We had a 3500 dually gas and traded for the 3500 dually diesel. The diesel walks circles around the gasser. I know I did not need a truck this big, but thinking down the road, it gave me the option to tow a TT or a 5er later we we change campers. It also gives me the ability to tow almost anything, including my brother-in-laws boat. The bed of the truck is 8 feet and got the shell specifically to carry our canoe (which we could not do with a 5er).
The choice is yours. But one thing you really need to consider - will you be trading for a heavier trailer in the next 5 years? If so, get the truck now? Are you planning on towing anything else other than your camper? If so, how much truck do you need. Is your truck a daily driver (a reason to go smaller).
What you need to do, just like selecting your camper, identify what you want to use your tow vehicle for first (all the reasons you will be using it, more than just towing your camper). Then narrow down brand: (Chevy, Ford, Dodge), then gas or diesel. Factor your personal finances and what you can REALLY afford (you do need to have disposable money for camping you know. What fun is having a new camper and tow vehicle and all your money goes to making payments and nothing left over for actually paying for campsites, fuel, and food?)
Use your head, think smart, and you'll discover what will work for you.