My husband and I docked at Calica two weeks ago. We were on the Holiday out of Mobile, Alabama. We took a Servicio Collectivo van to Cancun from Playa del Carmen. Their station is about two blocks west of the bus station in Playa del Carmen. We rode to Cancun for $3.00 each. We then took a city van to Puerta Juarez where we took the ferry to Isla Mujeres, a small island off of Cancun. We had a wonderful time.
We also returned to Playa del Carmen in a Servicio Collectivo van. They go back and forth between the two cities.
My husband speaks Spanish, which really helps us travel around in Mexico.