If you are planning on palace visitation in Seoul- I would highly recommend Changdeokgung Palace.
It's a smaller palace in comparison to the highly popular tourist crowded Gyeongbokgung Palace but that said, Changdeokgung palace is a UNESCO World Heritage Site.
There's a secret garden tour (extra admission fees apply) and it's definitely the highlight if you are into nature.
Bring your best buddies along because there are so many pretty backdrops and you'll probably need to allocate more time if you plan to cover the entire palace.
During my visit, I noticed locals coming in wearing hanboks to take couple shoots and little kids donning it while their parent snap away!
Maybe you should come prepared too for some well planned heritage shots.^^