Much appreciated!
Mostly the stairs are just for aesthetic purposes. In theory, you COULD make a second floor, though the only issue is for the ground on the second layer, it would have to be exclusively ground splines, since there can only be one layer of ground at all times.
Though, now that I'm thinking about it... If it were planned out very well and perhaps was made correctly, a 2 floor area would be pretty possible. 2 floors, bottom floor could have track running along the outside of the room, and the upper (or lower) floor could have tracks running along the inside, that way no ground would overlap if done correctly... And a helix or two could bring the tracks between floors. Might be a big cluttered, and the camera could have some issues, but it's possible... Now I want to try this :hehe:
Also, the assets used for walls/ceilings/staircase is by the user Hack, and can be found on the DLS by searching "MRR". They are made in both N and HO scale dimensions I believe.