Overall a good experience and would stay again!
House: Small but quaint old house in a decent neighborhood with ample free street parking. Very convenient access to O'Hare and nearby conference facilities (which charge up to $35/day to park -- Lyft/Uber rides are easily summoned from house). Door opens with key code; I had no issues.
Room: Shared room is upstairs with 3 beds. It has a cozy hostel-like feel. My foam mattress was comfortable, and sheets were very clean and new-appearing. No central air, but window AC unit was adequate on an 85° day. Fan is also provided. There is occasional noise from planes flying overhead and the highway nearby, but it was tolerable.
Kitchen: Some food is available (bread, peanut butter, grits). There is also a binder with local attractions and restaurant info, which is a nice touch.
Bathroom: There is only 1 bathroom shared between the up to 6 Airbnb guests. Mary has thoughtfully put a whiteboard "signup" list on the door, and it wasn't an issue the 1 night I stayed. Individual towels were provided at check-in. Bathroom even had some toiletry supplies available for use by guests.
Internet: wifi was reliable and fast!
Communication: Mary responded within hours to all of my questions and was very pleasant.