This is a nice walk around the 155 acre Fresh Pond Reservoir. There is one main path around the pond with options for short side trails. There are three main entrances at Alewife Brook, The Cambridge Water Works and Glacken Field but you need to be a Cambridge resident to park here.
By bike you can follow bike lanes on Concord and Huron Ave and you will find bike racks at the reservation. By bus you can take #72 route from Harvard Station down Huron Ave to the Parkway. By subway take the redline to Alewife Station. Turn onto Alewife Brook Parkway and walk by the shopping centers to cross Concord Ave near the shell station to reach the reservation. By car take the 250 Fresh Pond Parkway. Again, there is no parking available for non-Cambridge residents.