My experience from October 2008 is that only with a guide can you tour Tibet. We got one through our travel agent in Xiamen, Fujian,China. It was a private Tibetan guide but his driver had to be Chinese who were were told did not speak english. We ( 4 of us) never did believe that. On the road between cities there are Chinese check points all along and the driver had to buy passes that are timed to ensure we got to the next check point no earlier or later than what was on the permit. ( There is only scenery between check points and nothing to stop for). Our guide was wonderful and we were able to arrange our own times and destinations and we were allowed to vary it a bit. Base camp to Everest is 9 hours from Lhasha and very poor accommodations. Scenery in Lhasha is extra ordinary. Amazing trip -flew in from Xiamen and trained out - no altitude problems