Can I buy a ticket for a sleeper train on the day of departure to Lijiang?

Our trip to Yunnan province is only limited for 6 days only and we intend to visit Kunming only on the last 2-3 days of the trip. So in order to save our time we decided to go straight to LJ soon after our flight landed in Kunming. Can we buy a sleeper train ticket on the day of the departure? How about bus services? Can we buy a ticket 2-3 hours before the departure..? TQ