I second Acadia Nat'l Park, at this time of year it will be lovely. You might also want to try a whale watching boat trip (I know they don't have whales in MN!!) Lots of neat antique stores along Rt 1 in Maine. Visit LL Bean's store too.
Don't be put off by the southern end of Rt 1, it is very commercial. It gets better as you go further north.
On your way from Boston, you can stop at Salem, very historic, or Gloucester (scenic). The whole North SHore of MA is nice.