If you are a Tokyo reader, you should try this route sometime. Tomigaya is the neighborhood to the southwest of Yoyogi Park. The route takes you down Yamate Street, through the Komaba campus of Todai, and into Ohashi.
From there, you walk past (under) that funky interchange to the Yamate Tunnel (the one I missed the opening of in March 2010). From there, into Ikejiri, which is mostly a close bedroom community to the Tokyo business districts of Shibuya and Roppongi. A friend of mine heads an incubator school in Ikejiri, and they have a nice cafe there.
The round trip for the walk is 4 miles.