Hi we will visit ZhouZhuang in 22/12. I am buying bus ticket from Shanghai bus terminal.

Am I allowed to buy returned ticket prior to my trip to Zhouzhuang or I only allowed to buy bus ticket ( back home to Shanghai) when I reach Zhouzhuang?

Secondly. Should I book/purchase ticket on-line earlier or it is safe to buy at the ticketing counter upon my departing day?

Thanks a lot