We went to Gyeongbukgong Palace in the morning just in time for the changing of the guards at 10am. It is easily accessible by subway. Since it’s also the actual stop of the subway station.
It’s a huge park. If you were really to check the entire vicinity, it will take the whole day.
We did not rent a Korean Costume or Hanbok (it comes with a fee), because we see other tourists wearing it then wearing thick jackets/bubble jackets over it while walking around the area. It defeats the hanbok experience.
Since we’re just after the experience of wearing a hanbok, we decided to just have it on our last day in Seoul, by booking a Hnabok-wearing photo opportunity at the Seoul Cultural Center in Myeongdong, which is for free, since we only want it for the photos anyway.