So, I went off to Seongju before going in to work the other day.
Here's what I found: two nice low-mountain roads. The first was nearly all pavement but still had a little mountain trail vibe to it, the second was a lot more trail than road with a few muddy spots and a few rocky spots. Both were fun and peaceful to ride and not too far from home.
Please forgive my bare-bones editing. I did not have a lot of time to work on this project.
Enjoy~