If you live in Korea and need to escape the craziness of Seoul, I can highly recommend taking the 2 hour drive to Inje, in Kangwon. Amazing mountains, clean water and fresh air. It's quite high in altitude too, so you're literally in the clouds.
We headed up there this summer - it was gorgeous!
There are endless self contained accommodation options (pensions), camping facilities, or it's even close enough for a day trip if you get going early.
The area is also famous for white-water rafting - great fun if you're looking to cool off from Korea's stifling heat
Stop at one of the road-side stalls for some freshly cooked, locally grown corn (옥수수).
And on the way home, be sure to have some Chicken Kalbi (닭갈비) at one of the 100's of kalbi restaurants in Chuncheon.
Put Inje on your 'Korean places to visit' list.
Buses from Inje to Sokcho (W6500, every 40 minutes) go via Osaek in Seoraksan National Park's southern part and Yang·yang. Buses also run to Chuncheon (W7000, every 1½ to two hours) and Dong-Seoul (W12, 600, hourly between 7am and 7pm, three hours,).
Or if you can, the drive is spectacular. Just use your GPS, or if you don't have one, take what's known as the 'Romantic Road' - Number 46 to Chuncheon, and then on to Yanggu, then transfer onto No 31. Follow the signs from there.
We stayed in a lovely isolated pension which could only be accessed by Cable Car - Which the kids were wildly excited about. 바람부리 펜션 (Baramburi Pension).
Check some pictures in the Gallery titled 'Inje - A Weekend in the Clouds'