Gangtok is located east of Sikkim, India, and is the capital. Sikkim is an independent country ruled since 1641 by a hereditary monarch, the Chogyal, and it joined the Indian Union in 1975, becoming its second state. With the Kanchenjunga at 8,534 meters in the world (third highest mountain) and the affection of the people, Sikkim has become a very popular tourist destination in recent years.
Gangtok, located at an altitude of 5,800 meters, was built on the side of a hill and can be easily reached by road in a four- or six-hour drive from Darjeeling. There is no rail connection. Gangtok has its own Himalayan atmosphere that is characterized by being remote and mystical. However, do not forget the hints of a bustling modern city that it possesses. 
This face of modern life has unfortunately also left its mark: crowded buildings, traffic jams, beggars and landfills. The latter is truly the most important nightmare of many tourist destinations in India. One of the most recommended hotels is the Sonam Delek which is located on Tibet Road. This is a pretty good hotel, with rates not totally unreasonable. The staff are very friendly and the restaurant food is exceptional.
The city is a very busy place full of shops, restaurants, hotels, travel agencies, Internet cafes, etc. You can walk around the city but it can be a bit tiring. What you can do is hire the services of a local taxi driver who will give you a good tour of every corner.