Hi,U may wish travel on the retro bus to move around Kawaguchiko.. I use the retro bus to get to quite a few places including the music forest which was quite nice and beautiful and the natural living centre has a very nice views of Mt fuji on a clear day...
Though not exactly a ryokan.. u may wish to consider to stay @ K house mt fuji @ Kawaguchiko... It is really cheap, clean and cosy... Their staff are very helpful too !!!