I am assuming you are talking about PAC (big Blue, which may have been white when you were there).
The only walkway I can think of is the bridge from ASHO to the main building. It is not glass, but it has tons of windows. Different times it was actually closed down and no-one used it. So it could have been a hang out place for kids. And it does have a roof that kids would get on top of and run around up there. It runs parallel to L Ron Hubbard Way, so you could look out and see the street, or if you looked out the other side, you would see what we called "main mess" - the dining area. If you ran down the ramp and made 2 hard rights, you would be in that main mess area.
Steel door could be anywhere, I think. It was a hospital before the church bought it. I think the main one this refers to is the one tha
t is in the basement and was the door to the incinerator room from when it was a hospital. It was beaten in a few times. Most of the time that I knew that area it was the C/S office for the RPF. And really dungeon-like.
If you came down the stairs from the loading dock (which was also called North 40 back then), and made a left and went down the hall a bit, you would see it right there. All down that way are long hallways full of large pipes.
Does that help?