My S is registered for Explore USC. Can he sit in on classes while he’s there? If yes, how can he make that happen?
Yes! It’s possible to sit in on classes on the day of the interview. Available classes will be listed on the Explore schedule he’s given once he gets here! That’s how it was last year at least.
@LayraSparks Thanks! Did you find time to visit classes? The agenda seems packed with activities. 
I personally did not, because my interview was at 11:30 am and I had to leave for the airport right after (there is a lunch at Town and Gown to conclude Explore, but I missed that too). Some people chose to prepare for the interview instead of sitting in, but I would definitely recommend visiting a class instead! It’s easier if the interview is earlier in the morning or later in the day, but if your travel arrangements allow it, it is definitely doable! Also, activities are only on the first day! The second day, at least for us, was just the interview and the lunch (and the optional classes, of course). Hope this helps!