List of touge in Saitama (Japanese-only):
The pictures in the "ghostly vistas" section are pretty cool looking, too.
Notes to self: Something to research for later: Akiyama Koufun in Kodama, Saitama. Is everyone in the series named off of geographical features local to their home area?? Also, take a look at Masedou Touge (written with the "ma" in "aida" and the "se" in "Setou Naikai") as the possible location for the mysterious M-Pass (since I'm now pretty much positive that Mitsumine isn't -- drat.)
Oh, and just 'cause: There's a former castle site in Kodama. Not sure how much of the castle is still extant, though. It doesn't look like much is. But maybe there are still some old rocks?