You could implement a map of the world and the dungeons, it is very difficult to get horientated when you are further along in the game or have taken a long break.
You could make it a nonconsumable item in the inventory that calls a Common Event (There's a tab for that in RPG Maker's engine menu) when used; But it'd only be one picture for a potentially quite complex area. That I'm afraid I can't help with.
