On day 1 when we came out of bagdogra, we drive fir the most part next to the river teestA. A mighty Himalayan river that has been tamed for power generation by nhpc. But as you climb towards gangtok, to get to see it in full flow . For a city kid, you don't get to see huge Rivers to often. It's a beautiful river banked by mountains on both sides and the road though pock marked, is very scenic. Compared to konkan , ghats are not curvy so drive is smooth .