(1) In the map location, you can determine which map the Player goes to by defining the NSEW borders. Simply define the map that would be next to the map, or the map that you want the Player to go to next. Throughout my realm, I have roads and rivers and mountains. The Player stays on the road when he hits the border and the bordered map loads. Since the road matches the coordinates, he stays on the road from map to map. This way, the Player does not have to go to a "map of the realm" to travel through the realm.
You have Map G. East is Map H, north is Map B, south is Map M, and west is Map F. You'd define these in your map locations.
Sorry if you already know this, as I suspect you do.
But in Map B, the south border is Map G. and so on.
You can do this even when your "realm" is disjointed, even as space travel. It's a nifty way for you to determine where the Player goes once he hits the border.
In other words, no, you don't need for him to go to your realm map all the time. He can choose to do that.
(2) You would place your global in the map location window. That means that whenever the Player enters the map, the global would add 1. Because the Player would enter the map more than once when playing the game, you would need to define your conditional as greater or equal to 1. If it just equalled 1, then once he enters again, your map realm would not know that he'd been there, as it would no longer equal 1, but greater than 1. BUT if the global equals 1 or greater than 1, then you know that the Player had been in the map, so it would be revealed in your realm map.
Sorry I write so much.