I'm hoping you get an authoritative response, but, since the question is a really interesting one, I fired up Google Earth to check this out. (I seem to remember walking from East to West late, but not really, really late.) I assume you mean walking, since taxi would be the brute force approach.

It looks from the overhead imagery, however, as if the Ikebukuro-Ōhashi highway bridge, about 350m to the north of the station, doesn't accommodate pedestrians unless they're shaped like cars. Same for the southern bridge, even farther away by Mejiro station, on Mejiro Dori. You might be stuck taking a taxi.

Here's the reference for the Ikebukuro station:
http://bbs.keyhole.com/ubb/showthrea...ge&Number=3598