I'm trying to book hotels in Kashgar, Turpan and Urumqi for mid-May and am running into problems finding availability online. I'm not very familiar with the hotel situation in these areas. I'm looking for sub-US$50 rooms and have checked hostelbookers, booking.com, Agoda, ctrip.

Any suggestions for other sites or is it likely that there is availability but it's not online? ie do I need to try to lock something down now or can I do this on the ground?