Har Ki Dun Trek is a moderate 4-day, 47 km trek, topping out at 3,566 m. The route takes in Swargarohini peak views — mythological ascent of Pandavas; Ancient timber villages of Osla and Seema with pagoda temples; Vast alpine meadows carpeted in wildflowers (May-June); Rich wildlife — Himalayan monal, musk deer sightings possible. Best months: April–June and September–November. Watch points: Inner Line Permit required from Uttarkashi DM office; stream crossings can be tricky after rain — use trekking poles; bears have been sighted — make noise on trail. Fitness level: moderate, permits required, suitable for children with adult supervision. Nearest hospital: District Hospital Uttarkashi — 95km from Sankri, 4 hours by road. Network coverage: BSNL works in Sankri. No network after Taluka. Satellite phone recommended for emergencies.