Udo doesn't look or feel like anywhere else in Korea. The landscape is totally unique - rolling lush green hills. There are lovely little B&B's all over the place (called pensions in Korea) and the people are so incredibly nice. You can navigate most of the island by bike or on foot. I recommend staying at least two days so that you have time to really explore. Also be aware the ferry simply won't run if it's too windy or the water is too rough.