I came to Jeju Island,South from Kuala Lumpur by AirAsia flight. From the airport I took bus to my hotel which is very near to the Jeju Intercity Bus Terminal.
The next day, I took bus number 281 from Jeju Intercity Bus Terminal at 6.24 A.M and get off at Seongpanak stop.  I start hiking at 7.30 A.M. The weather was fine. It took me about 4 hours to reach the top of mount Hallasan. The view was breathtaking. It was a sunny day and was hot at top. You may spend some time taking photos when you reached the peak. I brought 1 liter of water and some buns for my hiking. It was okay for me. I walked down the Gwaneumsa Trail. It took another 4 hours. If you want to go back to Jeju Intercity Bus Terminal again, take bus number 475 from Gwaneumsa to Shancheondan Altar and switch to bus 281 to the Jeju Intercity bus Terminal. Every bus fare is 1,200 won which is very cheap. I stayed in hotel near the bus terminal. Bus terminal to the airport is about 15 minutes bus ride.