Are you bilingual? If you aren't, think about what questions you might have. Have your parents write those questions in both English and Chinese. You can then ask anyone for help by showing the appropriate question. A friend did this for us in Japaneses/English when we took the train and subway to her home in Yokohama. We found everyone to be extremely helpful.

Ask your parents about giving you a prepaid credit card in case a flight is delayed and you need to buy some food in the terminal. Think about what you would need to do if you are delayed into Chengdu and need to call your grandparents or they are delayed in picking you up. Do you have a cell phone to reach them, or would you need to ask someone to make a call for you. Be sure you take their cell phone number.