I just came back from Costa Maya, via Carnival Cruise lines,also took a group of freinds from BC over to AC, and up to property, they thought our trip was best of cruise, want to come back to AC, without cruise. It looks like Costa Maya is about 30 KM from AC border, could be wrong.
The property at Costa Maya, is also increasing in price like AC, so if the road north is not really a bad idea, or a joke. Could be a matter of time, Me, I am for this, as we could be supplied with goods and services cheaper from Mexico, verses by barge from BC.