Drive North on Route 128 until you reach exit 14. At the end of the exit ramp turn right onto Route 133 toward Gloucester. Stay on route 133 until the end of that highway. With the harbor in front of you take another right onto Route 127 South (Western Avenue). About a mile and a half down Route 127 south look for a left hand turn marked Hesperus Avenue.
You can see the green street sign about a third of the way up a telephone pole on your left, but more importantly there is a small blue sign on that pole which says "Hammond Castle". Turn left at these signs and the Castle Parking Lot is three quarters of a mile down Hesperus also on the left. You will see the entrance. Park and walk to the East end of the parking lot and walk down the stairs. The castle itself is straight ahead of you.
It is suggested that you NOT use a GPS device as it will send you the wrong way on any of these roads and highways which will delay your arrival here at the Museum.