Since 50 years have gone by and a lot of the story has been told:
YO-DO is located in WON-SAN harbor. It held "mysterious" people from "mysterious organizations" Yo-Do was under nearly constant artillery fire from the North Koreans.
When Sarsi moved to the west coast of North Korea, she probably visited the many islands on the west coast that harbored various South Korean Guerilla and Partisan outfits. Those boys pestered the hell out of the North Koreans and tied down thousands of the North Koreans and Chinese troops