The Langtang Trek can be done in as little as a week, but day hikes in the upper valley are sure to detain you for another two or three days. It takes about a day to get interesting, first following the continuation of the Dhunche road (a spectacularly destructive feat of engineering, built to reach a lead and zinc mine in the Ganesh Himal) up the unpromising valley of the Trisuli River before leaving the road and rounding a bend to Syabru in the Langtang Valley. The next two days are spent climbing briskly up the gorge like lower valley, where oaks and rhododendron give way to peaceful hemlock and larch forest; after ascending an old moraine, snowy peaks suddenly loom ahead and the gorge opens into a U-shaped glacial valley. Springtime is excellent for flowers here, and in autumn the berberis bushes turn a deep rust color..
Two Bhotiya villages occupy the upper valley: Langtang (3,300m), the bigger of the two, makes a good place to spend a night and acclimatize, while Kyangjin (3,750m) boasts a small gompa, a cheese "factory" (fabulous yogurt) and an attractive chalet-lodge. The Langtang Glacier is a full day's walk further up the valley. You'll want to spend at least a couple of nights in the upper valley to explore the glaciers and ascend the 5,033 metre Yala Peak ( Tsergo Ri), from which you can view an awesome white wilderness of peaks, including 8,013-metre Shisha Pangma.