I just read an article in Feb. 2015 issue of Car and Driver comparing the new F-150, Silverado, Ram 1500
and Tundra. According to the editors of this magazine, the new F-150 rated the highest overall. No doubt a very good truck.
But what struck me was the Ram 1500
they tested was equipped exactly like mine yet it had a payload rating, as tested, of 1530 pounds. I'm not sure how this was calculated but that payload rating gives me ample capacity with an AS with a tongue weight of about 800 pounds. It appears as though I'm overthinking the payload issue. I should now decide which AS we would like to have and move on.
Thanks to everyone for your collective input. It has been very helpful and it is sincerely appreciated.