I once had a nice commute of 15 miles each way, between Watertown, MA and Natick, MA. Now it is just from Watertown to Cambridge, 3 to 5 miles each way depending on route. But I have at least 4 different routes. Shortest and fastest is straight in on Mt. Auburn St. but involves lots of traffic, buses and narrow outside lanes with parked cars. Then there is Arsenal St, more space with wider outside lanes, but a little longer. My back streets route in between those two is longer still, with some good hills and views of the Boston skyline. Most pleasant, at least in the off season when not too crowded, is the paths along the Charles River, which can be varied by crossing at various points and using both sides of the river. There is even a quarter mile of wilderness singletrack at one point (Gerry's Landing aka Hell's Half Acre).