Thanks all!
@Ark: I guess the air bladders should be accesible for maintenace things, but I have not spent much ideas about it. The focus was on different gondola layouts. The circular things on deck 0 are generators, the tanks next to it contain fresh/used water.

@Ravi: Silo and Vue. I used the standard materials and atmosphere atm plus an additional spotlight above. Each deck is rendered sparately and an alpha mask overlayed in PS.