Highly recommend to visit this place if you are in Chengdu. Jiuzhaigou is about 4hours ride from Chengdu City via their high speed rail and car so for travellers with time to spare I suggest going a day early to stay at the hotel/resort near the park entrance and head over early in the morning before heading back to Chengdu in the evening. It is easy to travel around in the park as they have sightseeing bus which stops at the major spots so you don't really need to walk alot making it suitable to bring your elderly parents or young kids along.