I am thinking I could add a port on the top, maybe bottom too, between the engine cowlings. As for a bridge, I think something like this would more likely have a cockpit. It is probably not more than 2 or 3 decks (pushing it). My hunch is that the "saucer" is 2 decks, and the engine space is a mid deck. What it is really missing is windows. Even a couple cockpit windows would make some sense of it. Not sure where...