I have few questions as for Zhangjiajie National Forest Park.

1. Yes, there are buses back to ZJJ city from the park, and the last bus departs at 19:30 around. You'd better reach the bus station about 1 hour in advance to catch the bus. There are also taxis available. You can take either of them.
2. Yes, there are shuttle buses and taxis from Wulingyuan to the forest park. If you want to book a hotel in ZJJ, the Bajie Youth Hostel is suggested, which is neart the Tianzishan Daguantai. The transportation is quite convenient.
3. There are eco tourist buses in the park, the bus fare has been covered in the admission fee. As I Know, there is no English Sign on the bus, but at every stop you get on or off, you can see the signages and maps in English.Don't worry.
4. From the first bridge under the heaven, you can take the free shuttle bus to the Tianzi cable car station.

From Suoxiyu, take a bus to the lower cable car station of Tianzishan in ZJJ city. Then take the cable car onto the mountain.
5. Yes, there are buse available between Suoxiyu to national park entrance. You need take the bus at the main entrance of Wulingyuan.
6. Yes, you need to take the free shuttle bus down to the Wulingyuan entrance bus station, where you can take the bus to ZJJ forest park entrance. Taxis are also available.

Thanks a lot for answers!!!