Nice place for relax, better rent a car to drive around and you can arrange your own time as from one
place to another place might take up to 20-30 mins drive.
better don't ask for english taxi. They are more expensive but not as nice as the korean ones. Even if
you change your plans you can show the korean driver and do it without speaking korean. I went during winter but better avoid this period because it's cold. not as much as seoul but still cold. Though snow is really beautiful on the island. Plan for a 10 days trip in order to be able to do everything even climbing the main mountain (4h to go to the summit and 4h to come back). and going outside on the ocean part. Yatchs in pacific land are top and services are good. Take good shoes with you to not fall down.