You have a lot of research ahead of you, but let me give you a few rough rules of thumb: For your truck, I would stick with a travel trailer that is less than 30 feet long and weighs less than 6K pounds empty. You may add as much as 1K pounds to the trailer when towing (and maybe more), so I'm estimating that you'll be towing up to 7K pounds in reality. Yes, you can easily add that much weight. If you have a full 50 gallon fresh water tank, that alone is around 400 pounds.
Using those parameters, it then really comes down to floor plan. For example, do you want the living room in the rear? Island kitchen? Dinette or free standing dining table? Where do you want the TV?
Once you get an idea of floor plan, then you can start thinking about a particular manufacturer. The major ones all offer similar floor plans, so then it comes down to other factors like features, the look, water tank capacities (very important to me), warranty, etc.
Like I said, you have a lot of stuff to research but I would stick with the rules of thumb above and then go look in person. It'll be overwhelming at first but you'll soon find that you gravitate towards certain floor plans and designs.