HI Andreas!
I live in Jeonju, about an hour and 20 minutes north of Gwangju, but closer to
Maisan and quite close to
Seonunsan/
Yongseo. Is your schedule "set in stone" so to speak? I have Fridays off, so if you are free, you can take your pick of Korea's premier crags. . . and if you wanted to do trad, I've got gear and would be down for
Horangsan. Are you just coming for the climbing? In any event, Jeonju is a nice city, with lots of traditional culture and good food:-)