We did the trip similar to the other response, arriving the night before, staying over for an early morning tour and then driving to the next stop in the afternoon. My son was also very interested in the college towns, so we made sure to check them out as well. When you sign up online you can do a general information session and a tour. You can also check to see if they offer a specific tour for your major. For example, at UIUC, we did the info session and tour, and then did a tour and question/answer session with the business school. General tours happen almost every day, but the more specific ones are less frequent, so that dictated which schools we visited on which days.
Good luck to you! Make sure to enjoy and have fun and not get stressed out!