Departure from China

According to what you said, you are not eligible for the 72 hour free transit because you will stop in two Chinese cities, but the 72 hour policy stipulates that you are only allowed to transit in ONE Chinese city.
Of course, if your total transit time in PRC is less than 24 hours, you can enjoy the 24 hour direct transit. In this case, no entry permit is required.
Otherwise, you should apply for a transit G type or tourist L type before your trip.