The best time to go down to a campus for the best information is During the Week. Mondays through Thursdays are ideal for visits since campuses are generally in full swing. Visiting on a Friday may not be as practical, as students, faculty and staff might be busy with social activities starting Friday afternoon. High school holidays that fall on Mondays are often great opportunities for making college visits. Many colleges are in session on these days — and you won’t be missing any of your high school classes.
The Best Seasons: The late summer and early September before senior year are convenient times to visit, since many colleges begin their fall semester as early as mid-August. The spring of junior year is a good time if you’ve already researched colleges. Spring break is also good if you play fall sports or are considering applying under early action or early decision plans, which usually have application deadlines in November of senior year.
Don't attend a college visit during the schools breaks because lets be honest every student attending the college needs a break from their class schedule once in a while now check with the school to see if in the summer is a good time for both parties because sometimes the college could have summer sessions.
the only thing you should bring with you is a pen and notebook to write down notes and "Sweet Factors" of the school, be sure to also ask many questions that are beneficial to you when picking a school to apply to
Another thing to keep in mind is ask a college student attending the college a couple of questions about the college campus and life, but make sure that they are not busy with a lot of work for their classes.