tickets to Simatai and Gubei watertown

I have booked a room in one of the hotels in Gubei watertown. May I know if I still need to purchase an entrance ticket to get into the hotel?
Will there be any issue with me getting into Gubei watertown after 5pm - I'll be going there direct from the airport when I land in Beijing.
If I wish to book a night visit to Simatai - where can I make a reservation? The Town website doesn't seem to have a section for night tours.