If you are searching for a place that is convenient for moving around seoul in a short term trevel, You should choose my place to stay. Our house is located in very center of Seoul.
You can reach every hot place in seoul just in 15 mins!
The nearest subway station is Jongno 5ga which takes 6mins by walk.
Almost every trevel spots are near(not over 2~3km away) at my place so you don't even take public transportation but take cabs with only $3~4 one way or you can just walk.