A time can be set up for you when the professor is not teaching. If you play a sport, ask to meet with the coach. NCAA rules allow a student to meet with the coach during an official visit to the school. Make sure you have a sport resume with you. Ask to eat a meal at one of the dorm cafeterias.
Most colleges have some type of overnight accommodations.
See if you can spend the night in a dorm. Set up an appointment with the Financial Aid Office.