The last bus from Nainbagh to Dehradun is at 1545. There are also shared jeeps from Nainbagh to Dehradun and would charge you ₹200.
The bus takes your though winding roads of Mussoorie and Kempty. You would cross river Yamuna on the way. This is the same road that takes you to Yamunotri (the source of Yamuna). You should reach Nainbagh in 3 hrs.
After the lunch, we had a ride of another 14 km by a pickup van to Pantwari village. Pantwari village is the starting point of Nagtibba trek.
On reaching Nainbagh, I stopped for a while to realise that this is the point which bifurcates to Gangotri and Yamunotri. I was awestruck with the view and decided to cherish the moment by sipping a cup of tea. And there I met a clean shaved bald headed guy Sunil, who was the owner of a tea stall. Refusing to take money from the 'Guest from Assam', I was helped by him to find a shared Tata Sumo to Pantwadi (30mins from Nainbagh towards Gangotri). The Sumo driver (Arun bhaiya), another interesting personality helped me too in finding a place to stay. Himmatsingh Parmaar, popularly called 'Mamaji' provided me the accommodation in a very affordable rate as I was a student and recommended by Arun. I realised by now what Arun bhaiya meant by the phrase 'Pahadiyo me ab bhi jaan hai'.The same evening I met a guy at Mamaji's shop who was an intern at 'Goats Village'. Goats Village, a few kilometres uphill is managed by 'The Green People' promoting Eco-tourism, Organic farming, Rural development and what not. I was fascinated that something so unique has been set up in this area with minimum human settlement. After the fruitful conversation and delicious Garhwali dinner, I decided to sleep early and start bird watching as soon as I wake up the next morning.
This is the point from where one needs to take diversion to Pantwari in a pick-up.