You might also want to invest in an Ohara / Yase One Day Ticket. This costs 1500 yen (750 yen for children) and covers rail travel on the Keihan Line and your bus journey. It also covers travel on the Eiden Line from Demachiyanagi to the village of Yase, should you want to go there too, but for me that seemed like a bit of a detour from the main attraction.