We traveled to Sanmaki Yetgil (Old Road) early on a foggy Saturday morning, taking the tour bus option instead of driving. This option was best, because the roads leading into the park were being rebuilt and there was a lot of construction once off the tollway. The trails consist of a moderately difficult hike up along the "Old Road" trail, along the peaks, then down into Sanmaki Village. The village has coffee shops and Korean restaurants. Returning to the parking area, there are two options. Option 1 is hiking along the reservoir on dirt paths and wooden boardwalks. Option 2 is taking a boat from the entrance to the village back to the main park area (cost as of this writing was ₩5,000). The main entrance has shops, restaurants, and restroom facilities. The overall trail length is said to be around 4.4 km, but there are also several options on trails taken.
Getting there: GPS: 36°45'44.7"N 127°50'32.8"E, Google Maps: 36.762406, 127.842448, Waze GPS App: Search "Sanmaki Yetgil"