On what -- for lack of a better word -- evidence, does she base this assumption? I honestly feel more at ease in China than any other country in the world. Granted, I speak the language and have spent 10+ years in country, but I host guests from abroad all the time, and have never heard a single complaint. Believe it or not, people born after 1980 who live in BJ, SH, and even Xi'an tend to speak decent English, pretty much as a rule... especially true for the well dressed set, which is easy to spot.

If you've read many of my other posts related to this topic, you'll know I feel about guided tours both in general, and with respect to the sites you've mentioned. But, I hate beating a dead horse.

Insofar as your side trip is concerned, check out the XIY airport wiki in order to get a feel for what's out there:

http://en.wikipedia.org/wiki/Xi'an_X...tional_Airport

Basically, you can get from almost all of those cities back to Beijing, so XIY is your limiting factor (assuming you don't scrap Xi'an from your plans, of course). Bangkok could be a decent bet; just don't try to cram too much in because it would be a shame if 6 of your 13 days were spent in airports and on airplanes.