Theresse!
Wow! This sounds great with your sons building it and playing with it, too. It is so much fun when the whole family does it together. We have built several large sets that way, and it has been a blast.
The extension out the back is a great idea because it seems that PM houses never have enough room for the all the furniture you want to add. Luckily they have extension floors, balconies, roofs, and garages to add more stuff.
Glad you are enjoying your PM, Pgal
