Kosei Line + the Mackerel Road bus湖西線・若江線バス
JR Kosei Line Special Rapid from Kyoto to Ōmi-Imazu (47m, ¥990), then the West JR Bus Wakae Line over the pass on the old Saba-kaidō to Obama Station (about 1h, ¥1,350). It stops at Wakasa Kumagawa (29m) and Kaminaka.
Example: Kyoto 09:48 → Ōmi-Imazu 10:35, bus 10:45 → Obama 11:48. Buses leave Ōmi-Imazu roughly hourly from 07:05 to 16:45, and at 18:45 as far as Kaminaka.