From Cancun to Puerto Moreles, although a bus would have been possible we took a taxi, which is not cheap in the area anymore, just to save time and effort. There is a great bus station in downtown Cancun. From Cancun, you can get city to city very well, but where you are dropped for the smaller places or a sites you want to see may not be in the middle of town at a bus station, it may be the side of the road. It is worth checking out where the drop off actually is before deciding to take the bus. If you are not used to public transportation, Puerto Moreles would not be the best place to start. I've been wary of renting a car in Mexico so I've stayed where I could get easier access to transportation, day trips, etc. without a car. The website for Mexico's bus system is called "TicketBus".