Cheongju is most useful as several distinct last-mile zones, not one point. Osong is the rail gateway, not central Cheongju; buses or taxis are still needed for downtown, Ochang or individual sights.
Central and eastern Cheongju are the culture option, with Cheongju National Museum and other museums, galleries and historic spaces.
Ochang is a separate destination. Cheongwon Life Festival runs October 2–11 at Miraeji Rural Theme Park. The official guide lists buses 53 and 535 from Osong Station to Ochang Plaza, then a festival shuttle running about every 15–20 minutes from 10:00 to 21:06. Festival hours are 10:00–20:00; adult general admission is KRW 5,000, children and youth are free, and entry after 18:00 is free. Advance sweet-potato harvest registration is closed.
For families, Cheongju City is promoting a pop-up playground at Ochang Lake Park on October 10 from 11:00 to 15:00. Some rides use on-site wristband registration and can fill early. If rain forces a postponement, the city says it is planned for October 11 at the same place; check the latest city notice before departure.
The next Cheongju hook is the 2026 Korea Forest Expo, October 16–18 at Saengmyeong Nuri Park in Cheongwon-gu, with forest-policy and industry displays, hands-on activities, performances and forest-product sales. Current tourism-event data lists overall hours as 10:00–20:00 and booths generally 10:00–18:00; reconfirm details before travel.
Choose central Cheongju for a quieter museum-and-city day, Ochang for the current festival or family event, and the Saengmyeong Nuri Park area for the Forest Expo after October 11. Combining central Cheongju, Ochang and Sejong in one day adds unnecessary transfers.