Re beaches, I was doing some research and it looks there might be some nice ones in Chiba. I'll probably head out there in September. I forget the names. Might be hard to reach by train, which probably makes them even better.

I have been to Kamakura and the beach looks nasty. Reminds me of Nantasket, MA. I would stay away as suggested above.

p.s. Is it possible to swim at the Odaiba beach?