Dear Grace,
Thank you very much for your questions.
Please kindly be advised that it is possible to visit to Mt. Wudangshan from Yichang, where you dnowstream Li River Cruise end.
You could take Train628 (19:30/0044+1) from Yichang East Railway Station to Wudangshan. Then have a rest at foot of Mt. Wudangshan tonight. Then full visit to Wudangshan next morning. You could have 2 full days tour in Wudangshan.
Then take a Train621(1906/0007+1) from Wudangshan railway station to Xian, which lasts for around 5 hours. As it is not a train start from Wudangshan, but a train from Wuchang visa Wudangshan, it will be hard to buy sleeper tickets. Since it is not too long, if there isn't hard or soft sleeper, you could try to buy a hard seat tickets. Or you could book the tickets with local agency before you travel to China.
Hope the above is clear and helpful.
For more Xian tour, you could check our website:
/xian/xian-tours.htm
Should you have any further questions, please do not hestiate to contact with us
Best regards
Sophie Huang
Top China Travel