On Sunday, if you have time before or after the Yemilab tour, then please consider taking a gondola or hiking.
High1 Gondola runs from 9:30 - 16:30 every day except in extreme weather.
It starts from Mountain Condo - High1 Top. (~10,000 Won for each way )
When you have a hike down it will take 1:00 to 2:00 hours, a 4.4 km hiking course.
If you want to spend more time hiking you can hike to the top of the Baekun mountain from High1 Top, it takes 1 hour for the round trip.