Plus, trying to put a 4 wheeler in the 5.5' bed means the tailgate is going to be down, right??
Usually, your tailgate will hit the trailers tongue jack, or not leave much room..
I guess you can put it on it's butt, but that will have it's own issues.. Make sure you drain the gas tank first and strapping it down will be fun.. ;)
I think you've bit off a bit more than you can chew thinking you can load all that in a option loaded truck.. ;)
I've got an XLT loaded 4x4 SuperCab with 6.5' bed with #1920 payload per the sticker, but even that would probably be pushing it on it's sticker weights..
Good luck!
Mitch