If you do use a 20' container, I suggest thinking about having a "deck/porch", on top of the container, to be able to sit/eat/cook with potential for a phenomenal view. You might be high enough up to catch a breeze that doesn't touch the ground in some areas, which is nice for keeping the bugs away.
Although lower than the roof, check out the original post of https://expeditionportal.com/forum/...ld-slide-pop-or-otherwise-open-out-up.116279/... If we do, I'd want to be able to have a removable railing system that I could install when we're parked, to make safer to be up there.