Dear Nelson Every,
Thanks for contacting Top China Travel!
It shows that the flight (BK2760) between Guilin and Zhangjiajie is scheduled every day. But as you mentioned, this is off seasonand the flight will be canceld at any time. It is hard to say now. The airfare is RMB 730/person. It mihgt have discount in some times.
Any further request or question, please feel free to contact with us.