Is there train servoce between Xian and Jiuzhiagou? If so, how often and the ticket price please?

There is no train from XA to Jiuzhaigou. You need to fly to that place from XA or take a train to Chengdu and change buses to the valley. Only the flights and buses are operated between Chengdu and Jiuzhaigou.

For JZG, the hotel condition is not good. What is your budget for hotels? It is suggested to stay in the luxury hotels or local hostel such as MIGU International Youth Hostel. The hostel is about 800m from the entrance.

For Chengdu, you can live in a 4-star hotel such as Yinhe Dynasty Hotel with the price is around 400RMB or you can still look for a hostel such as Flipflop Hostel or Lazybone Hostel.