I think I nailed down the area to use. My wife would like to have an area for her sewing, that includes the shelf units along the brick wall. I'm fine with that. I made some basic changes that don't make much difference to the plan we last looked at. It is still quite a bit more room than the 11' 6" x 11' 4" room with the big glass door.
She even brought up the idea that several of you have; could I run a train from the existing room into this bigger room? Again, I would have to do it at about 73" high so I don't bump my head going through the doors. Unless, I put in a lift out section about 6 feet long.