A few more pics of the cargo box and sleeping platform showing the modularity I've designed into it.
Fridge mounted to sleeping extension:
Fridge and dog crate on cargo box:
Two dog crates on cargo box:
Fridge with sleeping pad:
I can also mount the dog crates toward the front, on the extension, but didn't get pics of that. Basically, I can mount any combination of items in any position/orientation for whatever the situation warrants.