The colectivo to Playa del Carmen stop is on the same side of the highway as the resort just outside the gates. They come by pretty often , 10 to 15 min wait at most. The stop for Akumal and Tulum is across the highway. For safety reasons, I suggest using the employee tunnel to get across the highway. (Walk towards the gate from Colonial lobby and take a right before you get to the gate.) Very easy. I always use pesos so cant comment as to if they take USD.
Here is a link to some more info from a great article.
https://unofficialpalladium.com/forums/topic/mayan-riviera-transportation/#post-4456