I travelled to Tibet in 2013 together with two friends. We were lucky enough to have the best tour guide ever, Gyaltsen, who showed us (a small part of) his homeland and answered all our questions. He’s extremely nice and helpful and speaks a perfect English. We had a private tour, which we planned in advance. Only bad thing is that it was too short, so I’m definitly going to go back and see more, and of course I will contact him again.