Here is the best single link I’ve found to get folks started on a Korea bike tour: http://kojects.com/korea-cycling-links-collection/
My Swiss friends Sibil and Bruno converted the digital guides to the Seoul-Busan route to pdf pages that are easy to use with an iPad. Their page is in German but has auto translate button in top left if this link doesn’t get their English version. They also blogged re their rides in Korea and Taiwan if you want another perspective. http://www.cleverpegontour.ch/unterlagen/
My mailing address is 4950 Wren Drive, Juneau, AK 99801.