I live just outside of Boston, MA- my communte is Somerville to Cambridge. Only 2.5 miles in but I have a lots of options to lengthen my ride home - looping around the Charles River for about 10 miles home or combining the Harborwalk trail (coastal Boston) with the Charles for about 23 miles. I can also combine the Charles River with the Minuteman Trail (Somerville - Bedford back and forth) for about 40 miles.
There are a few other trails I want to try.