thevalkyry
Queen of the Turtles
It is very easy. Once you pass through Customs there is a ADO counter where you buy a ticket to the old Playa bus terminal (5th and Juarez). Nice big modern bus that takes about a hour. From the bus terminal it is about 150 yards to the ferry terminal. ADO just went up on the price to 90 pesos. The best way to get to Playa from the airport and I think that you get a discount on the ferry if you fly VA.
Also - ADO has a booth on the ferry dock in Coz so you can get your return tix there when you get your ferry ticket to go back.