So we kinda cheated here. I ordered a Ford box without any mounting,or fender holes from midwest Ford. Easy assembly.
Drilled some holes,and put nutserts in to bolt it down. If you noticed I didn't install any of the cross braces for the bed. You will see why soon.
That was some pics with the fenders mocked up,as well as a few of the side panels we made to fill in between box,and running boards.
We also made some fender extensions,and a rear filler pan that will hold the plate as well as the lights.