some quick tips about Insubong:
1. Go early! Seriously, Insubong is populated with 4~6 people climbing teams and they take forever to climb.
2. Bring 60m rope to rappel. Better yet, bring 2x60m ropes and you will only have to rappel once.
3. If you are using subway, bring $2 (or was it $3? I forgot) cash per person to take taxi up to the trail entrance. Taxi will pick people up near a small grocery store. You will have to share it with 3 other people.
4. Depending on where you start, it's possible to pickup your bags on your way down, but if you are not sure (mostly due to climbing traffic), it's better to climb with your backpack. Rappel site overlaps with Dove's Route (비둘기길)
5. If you hear 낙석 (naksuk) Something is falling, if you hear 자일 (za il or "seil" if you are a German), rope is falling