Getting back to the grey water, most overland campers have less grey water capacity than fresh water. This means they are either not using all their fresh water they have made provision for, or they are offloading their grey water along the way (in a thoughtful, but realistic manner hopefully). I have even been in campsites in the summer, where the site operators have asked for campers to discharge their grey water around the trees on the site to water them!
Gator, is that your grey camper box? If the double bed is in that space above the cab, you must be like Wile E Coyote after been flattened by a road roller - that would give me the heebie-jeebies with my face so close to the ceiling!