Do not do three rings in one day
Do not put Gyeongbokgung, Hongdae and Jamsil on the same first day. All three have a metro, and the changes, exits and walking still eat the day. Learn one ring a day: palace and Bukchon, Myeongdong and the stream, Hongdae and Yeonnam, and one of Garosu-gil, Seongsu or Jamsil. A first trip schedules two rings, with time to get back to the hotel between them. One dusk light: N Seoul Tower or Lotte World Tower. Eat inside the ring you are already in. Do not open the next district just for another meal. Sitting at the hotel between the two rings is worth more than collecting a third ring on the train. Keep the night street in the district where you sleep. Do not transfer again for a stamp.
Airports stay in the transit note
Airports stay in the transit note, not on the place graph. The AREX express from Incheon ends at Seoul Station. To start in Hongdae, take the all-stop train — the express does not have a Hongdae stop to find. Gimpo is a different airport line. On arrival day, Culture Station and Seoullo are enough. Namdaemun can be the arrival meal. Do not add Jamsil, and do not attach a Hongdae night to the same day. Bukhansan is a hike. Trail dossiers here are off — do not write it in as a city next stop. With luggage, stay on the Seoul Station axis. Culture Station and Namdaemun are enough for a day. Do not transfer onward to Jamsil or a Hongdae night the moment you arrive.