> Looking for recommendations for a camp site
> anywhere within a 3 hour or so drive of the Tokyo
> area with cabins and (outdoor?) baths for an
> overnighter on 9/23-24. 

Haven't been to this place yet but it certainly looks good.  It's in Nikko.  http://woodsmans-village.resort.life.co.jp/english/e_menu-1.htm
Hope it's something that would interest you.

DougH