[SPOILER] Brennenburg Castle's overall layout (complete map)

[asciipornstar]

All the maps come from hidethedecay on deviantart. The individual maps are much more useful if you're actually trying to play through the game:
http://hidethedecay.deviantart.com/gallery/31525950

As you mentioned, with the elevator room flipped, the prison areas are directly beneath the back hall and the study/guest room area, so it's impossible to distinguish. I might upload another version with just the essential rooms tonight.