Talk about a trail biker's dream: Northern Thailand serves up an unexpectedly excellent network of surfaced roads from Chiang Mai to the Burmese boder. Then you'll find a series of little-known and largely unvisited dirt roads and tracks into and across the hills that make up the Thai-Burma frontier. Although not suitable for the beginner, and best avoided altogether during the slippery rainy season, the extensive network of mountain tracks has been mapped and written up by Chiang Mai-based trail bike enthusiasts. Stay at isolated villages established by the descendants of Chinese Nationalist soldiers, refugees from the communist revolution of 1949. Visit Karen, Hmong, Lahu, and Akha settlements, and gaze across startling, unspoiled vistas to the poppy fields of forbidden Burma. You can do it independently, but the experience is better if you take an experienced guide who speaks the local languages.