I think and early to mid 90's mountain bikes make excellent commuters. Put on some slicks to go faster. Change to some knobbies or winter tires for the rough weather in Idaho. You should probably check the local area to find out price ranges either through craigslist, coops, bike shops that sell used, or even pawn shops. Some had eyelets for racks and/or fenders as well.

Not all college campuses are the same as far as thievery goes. Your best bet is to check with the college or town police. Still, a good u-lock, locking skewers, and cable should be adequate. Remember some colleges can be in the heart of a major city while others are nestled away and isolated with one main artery to get on and off campus.