When the two pieces nearest the back are removed, the front piece can stay in place as a shelf. This makes the setup quite versatile, as I can just sleep in the bed and then use the two shelves to store whatever I have in the bed while I sleep. This is an easier setup to manage for short 1-2 night trips where I don't have a whole lot of stuff.
Trying to show some perspective on the two shelves in place. The top one is 2x4ft, and has a 1x2 lip all the way around it to keep stuff from rolling off, and it has multiple anchor points around the edge for securing stuff with bungees, nets, rope, etc. The top shelf rests on the top flanges of the side windows. It will promarily be used to store my fishing gear and other fragile, light stuff, so I don't think it will be too much stress on the flanges. On the bottom shelf here, you can see a removable lip that I have put on the back side of the shelf to keep stuff from slipping off. Again, it is quickly removable with bolts and wingnuts.
Another one trying to show the two shelves. The front edge of the bottom one fits up into a groove that runs along under the front window and also rests on the sides of the topper along the bedrails. It is very strong, I can lay down on it and it supports my pleasantly plump derrier. It can also be moved easily to the back of the bed to act as a prep/serving table for dinner time.
This is setup in the rear drivers side corner for now, but I will likely move it to a safer location or protect it somehow whenever I get around to making the final product. The 12V outlet powers the inflator to blow up my air mattress, and also provides a quick access point for a spotlight, etc. The pull switch powers a 12V light mounted in the top of the shell. I also wired another switch in the cab so I can turn it off from in the cab if I leave it one and don't realize it till I'm in the cab.