I've since made some not-quite-so-pathetic illustrations and it's time to share. If you, like me, are truly obsessive about this sort of thing, behold and enjoy. (Click to enlarge.)
These drawings are not remotely to scale, but FYI there is a reference in the book to the main corridor on Deck 3 being 40 meters long. You have to assume there are all sorts of little cubbies and access tubes and other Very Important Spaceship Stuff and whatnot in between the crew quarters, for example, because I'm here to tell you: those rooms are not each 10+ meters on a side.
Alpha Skiff airlock is where Edie is momentarily trapped with some serfs during the fight in the equipment hold.
Beta Skiff is the one Edie and Finn are marooned in, halfway through the book, and to get there they take the shortcut to its airlock via the extra ladder.