Problem with late evening departures
Check out early on departure day, a full day city tour, with no place to rest in comfort. In similar situations on other tours we had hotel bookings extended by half day. In Datong the guide and driver found us a two-star hotel room. You might be hesitant to offer it to guests who are staying in 4 and 5 star hotels, but we found it clean and comfortable. Sitting room, bedroom, bathroom for 80 yuen, very reasonable. You may have other ways to solve this problem, but we feel that it needs a solution for folks who are beyond the age of backpacking.

I think it would be useful to have options and suggestions for things to do on the rare "time at leisure" occasions. That includes local maps. We would have liked to see more of the cities of Kunming and Chongqing. A possible city tour? In some places the local guides took some initiative that was appreciated: Grace in Xian took us out in the evening; near Taiyuan the Qiaos Compound was included at our request and additional entrance fee; at Yangshuo a motorcycle rickshaw tour of the country side and a village (exorbitant price of 150 yuen per person); performances in Xian and Guilin, Naxi music in Lijiang.

Transportation
As you know, we had three overnight trains and two during the day. They were all fine. Our guides joked about China Air not being on time, but we experienced only one slight delay.

Hotels
Our hotels were outstanding, mostly well chosen for location and quality. We appreciated the guest house (no star) in Pingyao for its ambiance. Now I know what it is like to stay in a family compound, sleep on a kang on sorgum-stuffed pillow. Have you thought of finding a similar guest house in Lijiang old town? Mixing these kind of accommodations with the American-style ones adds to the experience.

Food
We had many good meals, a number of them chosen by our guides with care. In that respect the girl guides were better than the men, may be a coincidence. We did not like the tourist restaurants catering to the large crowds with bland tastes. The worst of these were at the Stone Forest near Kunming, and the first day in Shanghai. We begged our guides to avoid these places, but sometimes they did not find any alternative. In Sozhou at least our guide took us to the Chinese part of the same restaurant instead of the western buffet.

We enjoyed the company of the guides who ate with us. Sharing food is a great way to make friends and part of the cultural experience. All of the guides had to be invited, which is considerate. Some refused, quoting "regulations". We had a suspicion that they were getting real Chinese food instead of the tourist fare. In their place I would not have touched the tourist food either. But of course they were individuals, we could not force our company on them.
Having a choice of breakfast at the hotels was great. Having only lunch (no dinner mostly) was also a good arrangement, we could not eat another big meal every day. We had snacks instead.