Like Boston, Cambridge is a walking city with great public transportation. Irving House is a short walk from the Harvard Square stop on the MBTA Redline. From the Harvard Square T station, follow signs for the Church Street exit and go up the stairs on the left. You will be near the gates into Harvard Yard. Enter Harvard Yard and take the left bearing path across it to exit by the Science Center, north side of the Yard. Walk across the plaza/overpass, taking a right to walk along the path by Memorial Hall. When you are on the streets again, you will be on Cambridge Street. Two blocks along Cambridge Street, Irving Street is on the left. #24 is the first house on the right.
Exit the terminal and turn right, following the signs for all the busses (first row of traffic). The SILVER LINE bus leaves from the far right end of each terminal. The front of the bus should read SOUTH STATION. This ride is free, and transfer to the RED LINE at South Station is free, as long as you stay IN THE SUBWAY TERMINAL. So, exit the bus at South Station and look for signs for the Red Line bound for ALEWIFE STATION.
Exit the Red Line at Harvard Square, follow signs for the Church Street exit. As you leave the turnstile, turn left and ascend the stairs on the left. You will be near an entrance to Harvard Yard. Enter the Yard and bear left across it, exiting by the Science Center/Memorial Hall. Walk along the right side of Memorial Hall (looks like a church). When you get on the streets again, you will be on Cambridge Street. Two blocks down Cambridge Street is Irving Street on your left. #24 is the first house on the right.