Little kitty, who is tentatively answering to Zilla (short for Meowzilla/Miaoujira), got to explore more of the building today while I cleaned her room (the bathroom).
She's used the litter tray a couple of times (still more misses than hits there) and I found her sitting in her cardboard box today.
She's been a bit grumpy for a couple of days (I don't think she's enjoying being on antibiotics), so it was nice to see that she actively chose to hang out with me when she had more space available.
She and Al (the other cat who lives there) have now seen each other, but not close up. Introductions are for the future, as is her getting a full time run of the place.