By my knowledge, you can do all of the above. some colleges reimburse you for whatever money you pay to fly into the school if you live far away. tours of the campus are usually included in a visit and you can typically request to sit in on a college class, though that's sometimes restricted and depends on the school.
A good thing that occurred because of the howler sent to Ron Weasley was that it congratulated his sister Jenny for making the house team. Molly Weasley sent the howler to Ron in Harry Potter and the Chamber of Secrets for taking the enchanted family car to Hogwarts and crashing it into a tree.
