Besides Zhangjiajie to Pheonix Town, any other places to visit?

Hi all,

I will start my tour from Hanoi, Vietnam to Nanning, then catch train to ZJJ. I will spend 2,5days for ZJJ, then catch bus to Pheonix Town. I intend to stay here for 1,5days. I still have 3 days more in my budget but do not know which place should I visit. Could anyone give me suggestion/advice? I wanna come back to Nanning and then catch train to come back Hanoi after that.

Thanks so much!