This is so cool! The vibe oozes Appendix N, the map is great, and the mechanics are all very interesting. I also love how the nature of the location inherently suits a drop-in adventure into any campaign so that a GM wouldn’t need to spend time coming up with a justification.
I think my only feedback is that as a GM I wouldn’t be sure how to handle the “era” shifting around (the only thing that jumps to mind is seeing stuff change outside, but I get the impression that the building doesn’t have any windows).
Overall though, fantastic work! Also, I appreciate going tri-fold, it’s fun and different (and got me to actually print it out).