I would have to say I agree - you are going to be bust on payload. We have a payload capacity of 1864 in our ecoboost, and an actual tongue weight of 630lb. Believe it or not that payload goes mighty quick. Full tank of gas 223lb, driver 200lb, wife and kids, hitch, 2 mountain bikes, 2 kids bikes, stroller, kids toys, chairs, and a mass of fire wood we have about 500lb of extra payload. Now we can seat 6 in the truck so when the grand parents come we get closer and closer. No issue towing the trailer as we can tow 11,300 lb but payload .... another matter.
having been there and done that with an undersized TV (we originally tried a v6 pathfinder) you will be amazed at how much the weights add up, and you don't want to be second guessing the weights the whole time.
2011 F150 Ecoboost Screw 4x4 c/w max tow
2010 Roo 21RS