If anyone is interested in taking part in any event in Korea, then let me recommend the site marathon.pe.kr
On it are heaps of events of all different distances througout the country.
Most of the events are listed in Korean; as is the website. However some do have English options. Nevertheless knowledge of hangeul would certainly be an asset..
Otherwise contact me with a prefered date ( most events need to be entered about a month in advance) and what distance you want to run and I'll do my best to help you out.