About half an hour driving distance from Pyeongchang KTX station, this place is good for one hour walking into the forest. It would be difficult to visit without your own car being 22km away from KTX station with very little public transporation options around the area.

Free entry if you are a local (강원도민), but even you are from Seoul or other areas, the entry fee is minimal at 2,000KRW / 1,500KRW for teenagers and 1,000KRW for young children. The reason for the entry fee is this place is within the private area called Mill Bridge and time to time, they offer some activities such as ‘heaving stay’ and ‘one day healing class’ and there is a cafeteria with a small art gallery.
http://www.millbridge.co.kr/renew/main/main.php

For me – it was an impromptu visit without any reservation, pay the entree fee upon arrival.

주소: 강원도 평창군 진부면 방아다리로 1011-26

There is a place for you to drink natural spring water, Bangadari Yaksu, very carbonated which is good for your skin and digestion system. Personally I did not enjoy the taste of the water. You can buy mini bottle to collect the water from the cafeteria (I cannot remember how much it costed for the bottle but was less than a dollar).

Do not think too much about hygiene control, Yaksu water is believed to be the healty for ages in Korea. I remember following my dad to collect Yaksu water every weekend hidden inside forest and mountains when I was much younger.

Three short walking tracks to choose from, some photos from Mill Bridge:

It is about one hour break into the nature, trees, breeze for a good refresh if you have your own transporation and happen to be in 평창. 4.3 google reviews rating. Reviews say it is fantastic in winter covered in snow, recommend to stay overnight in the 펜션 and they have really nice hot chicken soup (백숙).