My ships have generally either been ex-naval vessels (in RT) or Inquisitorial ships (In DH) and so have had good technology. Key points on the ship will have elevators between them and exceptionally big sections of the ship (such as the main spine, gun decks etc) will have some kind of tram or mono-rail in place. The outer, bulky areas of the ship will have a plethora of access corridors, crawlspaces and ladders for the ratings to scamper about betwen decks and across levels.
Basically the bridge, command deck, officers quarters, main engineering deck, hangar deck and any purchased components of the ship (trophy rooms, librariums etc) wil be accessible through convenient mass transit systems. On the other hand if the players hear about Joe Blogs down in Aft bilge deck - level 17 running an illegal gambling then they are in for a long trip to go see him.