Rpg Maker Developers Group

Ok so im making the world map(the one that you go to when moving from location to location NOT the item that says your location) and what i want to do is. when you leave a location i want it to pop up a box that says where do you want to travel to then it give you a few locations and when the player selects a location it auto walks the player to that location, i only want the locations to pop up that the player can actually walk to like this

Green  [ ] = Places you CAN go

Red     [ ] = places you CANT go

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I want it to where the player can only walk to the closest areas. i dont want the player to be able to just walk over a town to get to a cave or past a tower to get to the lake. i want it to take the player to the next area so that the player has to go through that area then out the other exit to get to the other side of the map.

Now im guessing its gonna need to use player coordinates to say "ok, the player just came out of this town so the only places they can go is here and here" or somethin like that. but i have no clue on how to set it up. Any help would be much appreciated.