For the most adventurous people, you can reach FOSS and also back home, through the mountains from/to different train stations:
Gotemba line:
Suruga-Oyama
Yaga
Yamakita
Fujikyu line:
Fujisan
Gekkouji
Shimoyoshida
Yoshiikeonsenmae
Kotobuki
Mitsutoge
Higashikatsura
Yamuramachi
Keio line:
Takaosan guchi