After dusk
Dongdaemun only answers where today ends. Much of the wholesale is shut by day, so start at dusk. See Heunginjimun first, pick one category before the floors, and do not sweep every level. Go deep in Pyeonghwa Market or the history park, not both. Eat inside this loop, then close at DDP. When the silver building is done, stop. Do not open Hongdae, Itaewon or Euljiro as a second night district. If you already ate at Gwangjang, do not queue another meal. Leave before the last train. Do not time the night to the final one. Pick one category before the floors: clothes, cloth or accessories. Stop on those floors. Do not use leftover time to add Hongdae.