I painted bed liner on the interior surfaces of the box (sides, front, and tailgate) and am in process of assembly of the bed. Having a lift available really helps but I still need to determine the best way to install the bolts in the middle of the bed as I can not reach those locations from the outside.
I still need to install the rear cross sill, square the box (again), and tighten all the bolts/nuts that are in the bed strips (its a lot).