1. Kirara train stops at Kibune (Kibuneguchi 貴船口).
2. I have not visited Kurama onsen, but the user reviews in Tripadvisor is favorable in general, and this is one of very rare onsens in Kyoto, it would be nice, especitally after the long walk in the winter air.
The price for open air bath is 1000 yen per person. You can use free shuttle bus service from Kurama station which operates at every train arrivals. You must take your own towels to save some money :-).
Enjoy hot spring in Kyoto!