Chris, Sounds to me like you have this planned out well! Now I see why your wife was fine adding the table in such a nice room. Kids love to have play areas underneath or inside things. I'm glad you have a home you would like for a retirement residence even if you have to move in between!
You are smarter than I was. We went so many years without kids, that I built a layout that suited me. Up high, scratchbuilt buildings, delicate scenery. Neither of our daughters were interested. They watched Thomas on television instead! 
Now they are grown and married, and I am trying to get started on a new layout myself.
Everyone has to find what suits him or her and the family!!
