I went on a tour at VCU a few years ago. Everyone dressed casually (but no jeans), as D2B said. First we went into a conference room to meet with the dean of admissions. He showed us two applicant folders, an example of a student who would probably get in and one who probably wouldn't. Then we visited a lab, a clinic, a pediatric clinic, a classroom, the cafeteria, etc. If I remember correctly, the dean led the tour, but we spoke with a few students in the lab who gave us their input. We didn't get to see students at work because we visited on a day where everyone was taking a test (the boards, I believe?). It was a very casual and informative experience. But if you're touring around the time of an interview, I would dress up a bit more. Hope that helps. 🙂