I went on this tour last Christmas. Enjoyed it. It was freezing cold with temp of -5 and -9 but that didn't dampen our enthusiasm. There were times when our fingers were numb while taking the photos, especially in Beiging. You will need layers of clothes and proper foot ware. According to my Fitbit, I walked 89 miles in 14 days and walked 135,230 steps.
We were fed and watered well, I am vegetarian but had at least 12-15 items at every meal. All the hotels were excellent and had 'our' sockets so no problem with charging the phone etc, except the hotel in Shanghai.
You will enjoy the tour.
Dyuti