Travel trips on Zhangjiajie

Hi, I am Bernard from Singapore
1. Can someone please tell me which airport to stop at for Zhangjiajie and how to go to the town from the airport by public transport and how far is the distance.
2. Which period is best time to visit Zhangjiajia.
3. How many day is just right for my stay in Zhangjiajie and beside Zhangjiajie any near by attraction to visit please advise. (7 day to play with)
4. Can someone help to cater a systematic schedule for my visit and the attraction that i must not miss.
A Million Thank you in advance

Have a Blessed Weekend
Bernard (Singapore)