I don't think wheelbase or rear axle ratio play into your decision. I've always had a long trailer (33+ tongue to bumper), and I've towed with a Ram 1500 and Excursion, both with a wheelbase shorter than your F-150. With WD properly setup, it has always felt stable.
As far as the rear axle ratio is concerned, with that payload, you obviously have the tow package, which means your final gear ratio will be just fine for towing.
Best advice as stated above is to weigh the truck ready to camp (family, dog, bikes, etc.) to see how much true tongue weight you can load.
2005 Ford Excursion 6.8L, 4.56
2016 Eagle 324BHTS, P3, PP 3P