My hubby and i took this 3 year ago when we were down there. the waves were too bad to dive in AC so we went to CZM.
Flew from AC to Corazol??? taxi across to Chetumal and buss to Playa del Carmen. Took about 5 hours if i remember correctly. Be sure to get 'EXPRESS' bus and yes, they are cold and comfortable seats with movies (in spanish). ab