Keith and Mr.Peterson can’t go in the basement or attic so what if we just close off those parts.
For the basement a couch could be in front of the door and for the back entrance to the basement there could be a chain on the handles and there could be crime tape around the 2 entrances to show that the 2 areas have already been explored.
For the museum maybe the crow statue that falls on Mr.Peterson could be lodged into the attic blocking the entrance to the attic.