I drive a 2014 F-150 XLT Supercrew with a sticker payload of 1440. It pulls a Bullet Premiere 31BHPR that weights in at about 7500lb
Family = @ 400lb
Weighed tongue weight = 960
Cargo in the bed = @ 100-150lb
That puts me about 100-150lb over payload. I have towed it nearly 10,000 miles without incident, (outside of my own stupidity - nothing to do with weighs and speeds ;) ), including a 1600 mile trip through the mountains of Virginia and West Virginia two weeks ago with the first day having high wind warnings all through the mountains. The trucks anti-sway kicked in by cutting the cruise and gently braking 4 or 5 times at quite predictable locations, (breaks in trees, cresting ridges etc.), and that was before I really thought there was an issue.
The transmission fluid gets to around 200-204C on hot summers days and I have been assured by the dealer's head mechanic that I needn't worry about that temp until 219C.
All in all it has been a pleasure to drive.