Some advantages of going to open house weekends are that you not only get the campus tour, you also get to meet many professors and gather brochures from the various academic departments, clubs and other organizations. The schools we visited during open house weekends also had break-out sessions (20-30 minutes or so) that you could choose from, including financial aid, sports, housing, honors, extracurriculars and student employment. During open house weekends, both of my kids met the professors who became their academic advisers in their chosen majors shortly after they enrolled.
We found the open houses to be very informative and planned our college visits on open house weekends whenever possible.
The open house weekends are also a lot of fun!