Two well-known colleges for their usage as tourist attractions are Harvard and UVA.
I wonder to what extent MIT is used as a tourist attraction or, for that matter, Yale, Princeton, Stanford, Columbia, Berkeley and Duke, although, to be fair, Columbia is touristically overshadowed by attractions like Times Square, the Statue of Liberty, and so on, so forth…
But are there other colleges that actually see significant use as tourist attractions?
When we toured Princeton, the overwhelming majority of families or small groups were without a college age person. We had about 40 people in our tour group with only about 5 or 6 actual prospective students. There were two busses of just tourists that were visiting.
When in Boston, I went on a tour of MIT by myself. My son, who wasn’t with me, was considering it so I don’t know if I would be counted as a tourist or a prospective parent though.
University of Chicago has a great museum (The Oriental Institute) on campus, and the Wright-designed Robie House nearby, and so my family visited it with no prospective students in tow.
I believe many tourists come to Cville primarily for Monticello, and then come see the original grounds of UVa while they are in town. There also is a thriving winery tourism business in the area, and many people come into town because of the large UVa hospital complex next door.
Wisconsin has weekend walking tours that don’t contain the application/counseling/etc sessions that are offered during the weekday tours, so potentially they could be tourist tours.
I don’t know how common it is, but apparently the Claremont Colleges get tourists too. I found this out when visiting the bookstore which in addition to individual college items sells “Claremont Colleges” stuff. I asked the clerk if there is really much demand for that and he told me mostly just tourists passing through.