An older, high mileage 1/2 ton truck, towing at the limit of most ratings, would not be a good choice. Your truck is new, healthy, and very capable of towing up to all limits. I've driven a similar truck (not towing) with the 2.7 and was very impressed.
You know and understand the numbers. The GCVWR is a duty rating by the manufacturer, stating we will stand behind this drivetrain, when towing this additional wt. Since they will warranty that vehicle, at that number, I have to believe they are giving themselves a bit of wiggle room.
I'd get that trailer you like, get a good WDH, and if lots of towing in the mts, be sure to keep the trailer brakes adjusted properly. New trailers need a readjust in a very short time. Ford has a really good IBC, that is easy to use.
Jerry