I've read it, it's really entertaining. It's basically a collection of funny, interesting stories, however that's also its downfall - there's no real ending - however it is a travel log so you shouldn't really expect a gripping ending!
I watched a fantastic amateur documentary a few months back about a guy who walks from the bottom to the top of Japan. It's called 'Kintaro Walks Japan' and is about an American guy who walks from the bottom to the top of Japan in search of his father's place of birth, with only a small sketch to help him. Although it's highly entertaining, in my opinion it's actually a little too positive, and doesn't really highlight the true Japanese culture. 'Hokkaido Highway Blues' does a better job of that. 'Kintaro Walks Japan' is available free on Google Video, the this link:
http://video.google.com/videoplay?docid ... &q=kintaro
Actually, I'm thinking about doing my own hitchhiking adventure through Japan when summer ends (or when my Japanese gets better which probably won't be for another year!). Probably won't make a documentary or book or anything from it, but I'm hoping it'll make a good ending to my life in Japan.