Will you go to Xian by train or by air? The last bus from Xian railway station to Huashan starts at 20:00, so you are able to catch it if the train arrives at the station as scheduled. No direct bus from Xian Xianyang International airprot to Huashan, so you won't be able to get to Huashan if you go by air. The hotels on the Huashan Mountain are with quiet environment and good facilities. I think you can have a good rest there.