[Sangetsu]

If you get to Kanagawa (or Tokyo), take the JR Tokaido line to Yugawara station. Yugawara is a hot springs area close to Hakone. You can take a city bus into the foothills of the mountains, and follow the signs to Hakone (I believe there is a sign saying in English: "Shortcut to Hakone").

The road is scenic, with a river to one side. There are numerous hot springs along the way. Be careful on the road though, it is a popular place for motorcyclists and mountain bikers, and they sometimes move pretty quickly.

Hakone itself is crisscrossed with hiking and cycling trails, and there are numerous campgrounds throughout. On clear days you can see wonderful views of mount Fuji.