Getting to CoreStreet on the T
Take the red line to the Alewife stop. Use the escalator located near the rear of the train to exit the station. There will be a sign above the stairs and escalator saying "To Alewife Center". Upon exiting, make an immediate sharp left, followed by another left around the edge of the building. Then, take the first right onto an asphalt pathway leading to a parking lot. The pathway has a chain-link fence on either side of it and grassy areas beyond the fence.
One Alewife Center is the red brick building ahead on the left. The entire walk is under 5 minutes.