What to do there?

This has been my campus visit exp

1) College tour - You get to see the infrastructure, get a feel of the college
2) Class - Sit in a class. Get to see the teaching methodology. My personal advice - dont sit in basic classes like accounting, stats. They tend to be boring. Also, dont take it the exp too much to heart, if you didnt like it as it might be true for only that class
3) Talk Talk Talk to students. Ask they why they chose it, recruiting, teaching, student activities.. anything. Any secret tips to get admitted. And listen to what other students are asking. My most learning exp was listening to my fellow visitors.

Also most schools have prepared schedules for school visits. So you wont have too much planning to do.