Hi Bridgman,
You are right, it is a two-level addition out back and the Family Room is over the Home Theatre. If you rotate the bottom picture 90 degrees clockwise; the stairs will stack up. The area on the left of the stairs is an outdoor storage area (that was probably the reason you had a difficult time to figure out how they match).
I will be posting real pictures and you will have a better idea.
Final dimensions will vary; they are not finalized yet. We will have a chance to talk more about the dimensions of both rooms. I am counting on everyone's input.
A very important point . . . the budget is not unlimited.
