The thing that saved me was a physical pen and paper chart that I drew out with the character names listed on the left hand column and the scene numbers listed at the top. That way, whenever I found a new file, I went to the scene number and wrote the room abbreviation beside each person that was present during the scene. This helped me more clearly visualize who still needed to be accounted for and during what moments. Maybe a little extra, but it made the experience less stressful and really fun!