Why is Kim willing to travel with the Buddhist Lama through India?

Kim utilizes his travels with the Lama to spy on events and people. Kim leaves Lahore by train with the Lama with the idea to go East to Varanasi, the holiest of the seven sacred cities (Sapta Puri) in Hinduism and Jainism, which also played an important role in Buddhism. They both love to travel so they decides to visit there.