Here is something to think about.... the truck that you are most considering ..... does it have enough braking power to stop both the trailer and truck in the event the trailer brakes fail! This is not such a stupid question, as this actually happened to us a couple years ago.... no just once, but about 3 or 4 trips ... no brakes in the trailer and we limped the trailer home. After a couple visits to the shop, found out the brake wires on the trailer rubbed and were shorting out. This we finally learned after the 3rd time to the shop, and they examined both truck and trailer and still missed it the first 2 times.
Believe me when I say, my wife and I were truly on panic mode driving the trailer with no brakes, but at the same time ... completely confident the truck had enough "umph" to it to handle both flawless! We did take secondary roads, got off the interstae, and drove much slower, and I started braking much sooner, and prevented us from getting into any tight squeezes that might require a braking lock-down situation (which never happened).
So what I'm saying is, the bigger the truck, the more tires on the road, the heavier the truck body, the stronger the brakes, is the truck you want.
Far too often, folks consider only the towing ability ... they forget about the braking ability ... If you were in the mountains on the down hill side, and all of a sudden your trailer brakes when out .... what kind of truck would you want to be in? Then, you decide!