To get to Hakone from Kevin’s Guest House you take the Daiyuzan line train to Odawara Station .
Then you would transfer to the Odakyu Line train, and go to Hakone Yumoto, you could explore Hakone Yumoto and then take a very pretty Hakone Tozan line train ride up the Mountain or a bus further up the mountain if you wanted to. The train is better and faster than the bus.
Daiyuzan line runs every 11 minutes. Last train from Odawara is 11:34 pm.
Odakyu line and Hakone Tozan line trains run about every 10-15 minutes.