Jan Boonstra's Web Page <-- This is the "man" when it comes to touring Korea.
Good detail of roads etc. If you use some of this route on a tour yourself.
Some trails around here only 3 or 4 in Korea
This is the only real mountain bike web page I have found.
Ever wanted to tour around the world? Here is a guy who did. Pretty amazing stuff.
This is the only real mountain bike web page I have found.

Lespo Bike Shop in Taegu or Daegu.