I was doing some research on a trip to Tibet for friends that plan to travel there in August. But it seems that this is not the best time to go there. The reason: the newly-opened Qinghai-Tibet railway (the highest altitude trainride) encouraged a lot of Chinese to make the trip to Lhasa, and tickets are sold out long in advance. Not that my friends wanted to travel by train, but the problem with all these additional tourists is that also all hotels in the city are fully booked (occupancy rate is 97%, which in reality means that you cannot get a room). And even if you have a room you might still not be able to see the tourist attractions. The famous Potala palace only allows 2300 people per day inside its walls. No problem in the past with just a few flights per day, but now that trainloads of tourists are arriving this is not enough.
The Shanghai Daily had an interesting article about some of these tourists. It turned out that many booked sleepers with travel agencies (the overnight trip from Xining is 27 hours), but ended up getting hard seat tickets. Some cancelled the trip upon hearing this. Several travel agencies are now canceling their package tours, because they cannot guarantee train tickets. Tourists also do not realize that Lhasa is located over 4000 meters high, and that this can cause altitude sickness. According to the newspaper, tourists that unexpectedly got sick then tried to claim money from their accident insurance company, but of course they were turned down.
Likely the surge in travel to Tibet will reduce once the summer holiday is over (and once this kind of article appears in more newspapers), but for the next couple of weeks I would stay away from a trip there. A good alternative could be Western Sichuan, the area to the west of Chengdu, which is quite similar with a very wild landscape and many Tibetan monesteries. Maybe not exactly the same, but at least much easier to reach (you can rent a 4WD from Chengdu, or even bike there if you are adventurous), and certainly much quieter!