What is the best route to take (No 919 or S2 train) Badaling Hot Spring Resort, Beijing?

You could take S2 train to Yanqing, where the resort is located. From the Hotel Kapok, you could walk down along the Nan Chi Zi Dajie to take subway Line 1 at Tiananmen Dong station and then transfer to Line 4 at Xidan station. Finally get off at Xizhimen station, from Exit A of which you could walk to Beijing North Railway Station. Here, take a train to Yanqing Station.

Upon arrival, you could hire a taxi driving to the resort quickly.