Does anyone know a good way to travel from Tunxi (Anhui, Huangshan) to Zhangjiajie (Hunan) ?

Hi, transfering in Zhuzhou can be a good option. Or you can transfer in Chansha, but only one schedule of bullet train is available from Huangshan North Station. It shall arrive at Changsha around 20:00, when buses to ZJJ have been out of service. You can still use this way if you are interested in staying overnight in Changsha.