The "lost" (from the Bible) years were spent in Ladakh, India as a Buddhist, holy man, and teacher (tslpl.org).
Gruber and Kersten (1995) claim that Buddhism had a substantial influence on the life and teachings of Jesus.
They claim that the Jewish traveler to India (and Sakka-like savior of humankind) was influenced by the teachings and practices of Therapeutae, described by the authors as missionaries of the ancient monastic Buddhist Theravada school then living in Judaea.
They assert that Jesus lived the life of a Buddhist and taught Buddhist ideals to his disciples. Their research follows in the footsteps of Oxford New Testament scholar Barnett Hillman Streeter, who established as early as the 1930s that the moral teaching of the Buddha has four remarkable resemblances to the Sermon on the Mount."
Some scholars believe that Jesus may have been inspired by Buddhism and that the Gospel of Thomas and many Nag Hammadi texts reflect this possible influence. Books such as The Gnostic Gospels and Beyond Belief: the Secret Gospel of Thomas by Elaine Pagels and The Original Jesus by Gruber and Kersten discuss these theories [and Holger Kersten's Jesus in India].
Jesus' travels in northern India (reluctant-messenger.com)
The Buddha Dharma Education Association lists on its Buddhanet.net website a Timeline of Tibetan Buddhist History. According to their historians, Buddhism begins to enter Southern Tibet about 150 years after Jesus' Passion [crucifixion and escape to India], or c200 C.E. Buddhist scriptures begin to influence Northern Tibet several decades later.
In 1887 a Russian war correspondent, Nicolas Notovitch, visited northern India and Tibet. He claimed that, at the lamasery or monastery of Hemis in Ladakh (Buddhist India), he learned of the "Life of Saint Issa, Best of the Sons of Men." Issa is the Sanskrit and Arabic name of Jesus. More