Alright well I'm currently at 67/72 locations found. Is there a chance that there is 5 locations at the prison to discover? I'm thinking I missed a few back on the main island. Once I get this achievement out of the way, I'll go on to the prison...

nope it restarts the game for you so its a new game plus you keep your lv and your inventory but the game just restarts and that is it so before you go to the prison besure to explore as much as you want and can before going because you cant go back...

You beat DI? Does it put you back in free roam after the prison?