Dujiangyan city is easy to reach from Chengdu. You can take the bullet train , it takes 40 minutes and costs 15 CNY. I suggest to buy a ticket in advance ( also the return ticket) especially in the high season, because they have reserved seats , if you do not have the ticket , you may miss your train. Trains run from 7 in the morning till 7.40 in the evening. The train is not only very fast, but also very comfortable and clean with a lot of space , even for luggages. Bring your passport , you need it for buying a ticket. Bring a paper with the name of the stations in Chinese characters, Without it it is impossible to buy a ticket, the stuff do not speak English. Leave plenty of time to buy a ticket and get in to the station, because you have to go through several security check to get in. For us it took 30 minutes to buy a ticket and get in to the train.
From the station you can take the local bus 101 (2 CNY), it is about half an hour to reach your destination. They do not give you change in the bus, you have to have the correct amount.
Mount Qincheng is a lovely are if you like hiking and do not mind taking the stairs (a lot) . For 90 CNY your are allowed to enter. You can easily spend hours, even a day there, if you are up to mountain hiking. After 20 minutes walk you reach a lake ( there are signs in English which is great help) , which you can cross by a boat (5 CNY) and take the cable car from there ( 60 CNY return ticket) . But you must go on hiking if you want to reach the top. You must take the same road back to the entrance.
In the mountain you find lovely shrines, pagodas, taoist temples. But you have to pay extra (between 30-60 each time) if you want to enter.
Do not go there for quiet time, it is so crowed with tourists, especially Chinese and they are very loud, shouting, talking on the phone all the time. It was not refreshing or relaxing at all, and it is a rip off with all the entrance fees.
We combination our trip there with the irrigation system, spend the morning there and in the afternoon in the mountain.
We preferred Mount Emei, less tourist, more pleasant place.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.