The 180km southern highway from Trashigang to Samdrup Jongkhar takes at least six hours. Shortly after leaving the town, the road winds its way up, though terraced fields up to Kanglung (22km/45min) at 1870m, where you can see extensive campus of Sherubtse College. Then the road climbs and crosses Yongphu la (2190m), cuts across the ridge into another valley, winds down slightly to Gumchu and then around the corner, arrive in Khaling, spread out in a high side valley above the Drangme Chhu. Khaling has a large High School campus, small town, a Institute for disabled (a school for blind and other disabilities) and around 3kms beyond Khaling, is the National Handloom Development Project operated by Women’s Association of Bhutan. After Khaling the road traverses above the small villages, fields and crosses Kharungla (2350m) and almost immediately after a short decent, climbs and crosses another pass at 2430m. Curling around the ridges and narrow valleys, arrive at a pleasant town of Wamrong (2130m), where the travelers stop for lunch. From Wamrong it is around 20km/45min to Pemagatshel junction, mostly descending through small villages, with views of distant houses and plains below. Pemagatshel town is around 29km/45min drive each way along this side road. It is the district head quarter of the smallest district in Bhutan. Unless you have an extra day for excursion, there is not much to do in the town. From the Junction, continuing south, there is stretch of road called Menlong Brak, where the road is cut through sheer cliff and makes amazing decent till Narphung. Then cross the ridge and climb to 1920m before making the final decent and arrive in Deothang (800m) after about 2hrs from Pema Gatshel junction. Deothang is dominated by a large Army camp with few some shops and road workers homes. From Deothang, it takes around half hour to cover 18km descent to the valley floor. The vegetation changes almost abruptly to Sal and teak forests as you enter Samdrup Jongkhar.