I think on the map page there will be a seperate map of the world. You'll just click on the area that you have downloaded and the main map will automatically move to that region. Just a guess but it would mean that it would only have to be changed once in the game and then it could be used for all future scenery releases.

But I'm sure that as it stands right now, as soon as you open up the map it resets your A/C position to the outer boundry when you return to A/C from map view. So you can only fly continuously if you never open the map. I think, because some strange things were happening to my A/C position when I tried to fly out as far away as I could.

 

This is correct. Opening the Map while outside the area displayed on the Map will teleport you back to the edge of the Map.

 

I'm hoping that they will simply expand the Map boundaries in the direction and distance needed to take in new territory as it's added.