Thinking about it a bit more, you don't need to worry about maps enabling "Sail To". You'd have the code to open the beach at the same quest case where the player receives the map. Normally "Sail To" is opened up when you get a map, and it's the possession of the map which does it. The end result is the same, just by different methods - you can't Sail To the beach until you get the map.
The map for Aruba is going to be an interesting case. Aruba is uncolonised in "Early Explorers", though you can visit it if you can find the landing points. Where you would normally moor to go to Oranjestad, you can still moor but it's now just a shore. Reloads are set to bypass the town so you can walk from one shore to the other and also visit the Indian village. Because Aruba is uncolonised (and was previously impossible to visit) in "Early Explorers", the normal map is not for sale. So your quest map will be the only one available. (And when the player lands at that shore, you're probably going to have Blaze or Bonnie say that this would be a great place for a port. )
The map for Aruba is going to be an interesting case. Aruba is uncolonised in "Early Explorers", though you can visit it if you can find the landing points. Where you would normally moor to go to Oranjestad, you can still moor but it's now just a shore. Reloads are set to bypass the town so you can walk from one shore to the other and also visit the Indian village. Because Aruba is uncolonised (and was previously impossible to visit) in "Early Explorers", the normal map is not for sale. So your quest map will be the only one available. (And when the player lands at that shore, you're probably going to have Blaze or Bonnie say that this would be a great place for a port. )