Point of departure: Seoul Subway Line 5, Gwangnaru Station, Exit 2
Point of arrival: Seoul Subway Line 3/Bundang Line, Suseo Station, Exit 5
(or you may run the other direction)
As per all sections along the Seoul trail, follow the orange ribbons, Seoul Trail signs, and floor markings. The course is really well marked.
"This course travels along Gwangnaru Station - the Hangang River - Godeoksan Mountain - Iljasan Mountain - the Tancheon Stream – Suseo Station. The course extends along the Hangang River, the Seongnaecheon Stream, and the Tancheon Stream; a forest path through the gentle slope of Godeoksan Mountain and Iljasan Mountain; and paths through villages. The paths through downtown areas, villages, and forests contain stories of local history, legends, and villages."
Further information available here: http://english.seoul.go.kr/service/amusement/seoul-trail/03-seoul-trail-courses/