Great, Bob!
We rarely play both Europe and Pacific at the same time - it is a lot to manage unless you have 5-6 players or more. . .and when we do we usually play the 1941 scenario - otherwise it is a little slow for the Pacific theater players for the first quarter of the game. But, yes, when we put them together it is a 4'x12' map not counting room on the sides for battle boards and country charts. . .