Adding the side box bottoms (5/8" ext. ply) and tops (1x I had kicking around). I'm poor, so everything is done as cheaply as possible, but also as strong as I can make it:
I intend the high side boxes to be for hand tools, woodworking to port, mechanical to starboard (in case the truck breaks down, I don't want to be standing in the road while I'm fishing for sockets). Power tools will go in the bottom and maybe the side drawers. Depends how everything fits. I cut the front bulkhead to follow the cab shape, minus 3/4" for the thickness of the side box doors.