I ended up cutting short my comments last evening because our older daughter kept texting me about some repair questions at their fix-er-upper house that I need to go over today and take a look at. I couldn't keep my mind train on the right track 
so I just signed off and posted a partial reply.
First business: Marty, yes we did get an agreement on the new real estate. 
I need to keep a 36" wide path from the door to the stairs and garage that shows in the upper left of the plan, to the door to the patio on the right side of the plan. That is my rule, so I can move anything that will fit through the exterior door on through from front to back of the house. Second, I keep the space on the lower right next to the door open for a sewing area for my wife. We both can use the existing train room for model and sewing storage and a workbench. Heavy duty work is done by me in the garage. She also may use one former daughter bedroom for sewing after they move a bedroom suit out which wouldn't fit around an oddly positioned closet in their present house. Demolition of that closet is underway.
Also notice I updated my topic title and link in my signature line to reflect the expanded area we have to work with. I am going to address the cassettes, yard, and broader curves in my next reply coming shortly.
