The brakes on that F150, like all other "half-ton" pickups, are not much heavier than passenger car brakes. I towed the small trailer in the sig below across the Rockies last Fall, and used the methods mentioned above to apply the brakes when needed. Used tow-haul, kept the speed to a safe and reasonable rate, downshift manually, and applied the brakes moderately for very short periods (2-3 seconds). It maintains control well.
BUT, those cheap thin rotors got too hot and warped. The front brakes pulsed noticeably afterwards, and when I got back home I had to have the rotors turned. The brake pad material was fine. Just scuffed up the pads on a flat board with sandpaper, and they were good to go.
I was surprised at the difference between F150 brakes and the brakes on my former F250.