The bike path crosses parts of Hadley, and it's worth taking it all the way down to the former railroad bridge over the Connecticut River. In season, you can watch the campus crew in their early morning runs. Cars are very courteous of bikes, despite the lack of sidewalks.
Taxis are available check a local telephone book but they're not so local and can take a while to get there.
Most people have cars, and that's your best bet. There is a car rental right off the highway in Hadley.
Walking is possible, but it will take you a while to get around, and note that most of Hadley has no sidewalks.
