That's a VERY ambitious two-day schedule you've got, there! Each leg is over 100 miles, so you've got a LOT of riding to do. But hey, since you asked, Amherst is a very nice town, with plenty of restaurants and little shops and green spaces. You also wouldn't have to go far out of town to find a quiet little camping spot either, I don't think.
Getting to Fitchburg on your bike and then taking the train could make your second day easier - Fitchburg is a mere 50 or so miles from Amherst, which should be a snap after getting to Amherst from New Haven!