I would recommend dressing casual. There are lots of forms of casual...and I don't know what your personality is...jeans, sweatshirt, sweater...pea coat? Polished but casual so that you are comfortable with your appearance and you will be doing lots of walking! You could even wear yoga pants and a nice sweater with a down vest on top with tennis shoes...you can make so much stylish but comfortable. Trust me, I live in Colorado...you can be trendy but not excessive for the situation :). Have fun!
Just wear what you would wear to school. People on campus pretty much dress the same as in high school. Though you have some people who wear pajamas and stuff because there's no much of a dress code in college, and then you have some people you wear more polished things like business casual type of wear and makeup.