Hi, I will be staying at Chadianzi, and planning to go to Dujiangyan by bullet train.

You can go to Chengdu Railway Station or Xipu Railway Station to catch the bulle train. Xipu Station is nearer and you can take a taxi to reach. For the train tickets, you can get upon arrival or book in advance. If interested, you can turn to Travel China Guide, which is a good travel agency. Their contact is bookingtravelchinaguide.com if you need.