For a car-free Jecheon trip, separate 'getting to Jecheon' from 'getting to the attraction.' Jecheon City's tourism site organizes trips by city, northern, Cheongpung and southern zones, and its Cheongpung Lake material places the lake area in Cheongpung-myeon rather than in the station district.
Once you arrive, use Jecheon City's official traffic information center instead of relying on an old blog route number. The system provides live bus locations and arrival estimates, stop search, route timetables, traffic and parking information. The city's timetable page also distinguishes weekday/holiday and school-term/vacation schedules on some services, which is exactly why a static screenshot can become misleading.
If you are heading to Cheongpung Lake, the cable-car/heritage area or another outer attraction, check both the outbound and return trip before you leave the city hub. Rural frequencies can be much thinner than central-city buses, and a missed return service can turn into an expensive taxi ride. When a route is unclear, search the attraction name and stop in the official system or ask the tourism/transport desk before boarding.
For a practical day trip, group attractions in the same zone rather than zig-zagging between the city center and Cheongpung. If your final attraction has a fixed admission or cruise time, work backward from that time and leave enough buffer for the local-bus connection.