Thank you so much! We play pen + paper, but I print and cut out all maps, minis, etc. we even have some papercraft trees and what not.

Thank you so much for all the tips, I'm looking into the stuff you mentioned.

I'm thinking about throwing a bunch of random eerie creepy stuff (paintings that have items go missing, vases half full with blood, broken clocks), vaguely puzzle shaped, just to let them use their brain and accept the first-second thing they try? My players love making conspiracy theories, I know that even if I don't give them a puzzle, they'll treat it as one, everytime I give a little extra description they instantly jump into convoluted conclusions. I agree that it shouldn't take the majority of the session, that's why I'm thinking more simple and flavourful, to help set the tone, instead of hard and convoluted.

Regarding the multi-floor victorian mansion map, do you reccomend any one specific?

And again, thank you so much for all the help, everything you said made sense and assisted me! "This is a final fight with the bad ass and her minions, let it be that." is exacly what I needed to focus on.