I am in Osaka right now just off to Nara for the day. The train system here is mega confusing with far too much choice. If you get in touch with the tourist information office in town they will give you a different story to those at the airport. Then the hotel will give you another option. If you can find someone who actually lives here then you are likely to get the real answer. We have bought a Kansaii rainbow pass and you can choose how much to spend on it, we put 5000 yen on each one and it seems to cover us for Kyoto, Nara, Kobe etc