Class is not optional. It's not summertime all year, plus you can use them for fall and spring picnics. Indispensable for winter, which include wet weather and many snow fights. Dress at MHC is casual. One old MHC saying is that college is four years when your clothes don't necessarly have to match.
Comfort is the main goal.
Plan for hot days, along with a few cold ones too. Bring a large supply of socks and underwear to avoid doing laundry often. There are a few activities that may necessitate more formal atire, but it's entirely up to you. Friends will also let you borrow dresses and other formal wear. For use when you've run out of space on your floor.