Great view. From that overlay its apparent that they are extending the MK into previously unused back stage areas as well as totally changing the area from the old 20K Leagues show area out through Toon town.
BTW, does anybody else remember when Toon Town started? Originally (1988) it was just temporary structures themed to Mickey's Birthday Land. It was only supposed to be up for a year or so, but it proved to be such a big draw that the land was made permanent. Of course, you could only celebrate Mickey's 60th birthday for so long, so it was re-themed to Toon Town.