In the above picture, if my "Harry Potter dorkiness" is correct, that bridge that you see, is the Viaduct to get into the main entrance to the castle, which is the first place you see when Harry walks in, in the first movie, goes up the stairs, and see's professor McGonnagal, and she talks about the sorting hat. Off to the sides of the stairs on the inside is a set of downward-spiraling stairs that lead to the dungeon, in which it's depicted in the 6th book alot, as Harry has to go to detention with Professor Snape quite a few times.
Whether or not there going to be that detailed with the inside of Hogwarts is beyond me.
(I really need a life. )