Imagine yourself in a schoolroom in one of the most remote regions of one of the hardest-to-reach countries on earth. Nepal. The Lower Mustang region to be exact. To reach it takes a 14-hour flight from New York to Doha, Qatar. Then four hours by air to Kathmandu. Transfer at one of the world's most dangerous airports to a 90-minute flight to Pokhara, followed by a jarring, eight-hour Jeep ride over a vertiginous dirt road — one side is a mountain...