I think the questions to ask can vary from student to student but, these are some we asked we when were doing our visits. I am sure we asked more but this is all I can think of right now.

What academic elements are considered in the admissions process, for example:
courses, grades, test scores, rank, essays, How important are each of these factors?

What size are the classes you could have as a freshman or sophomore? How
many large classes can you expect?

Who teaches the freshman classes? Teaching Assistants? Graduate Assistants?

Can freshmen have cars on campus? What is the fee for having a car on campus?

Is it easy to get around campus? Can you walk to and from classes?

How many hours a day do typical students study?

What are the most popular majors?

What help is available for tutoring, personal, and career counseling?

What are the computer facilities on campus and in the residence halls?