Thanks for the great response. After standing in the space again and working throught some of the changes with my production assistants I think we have settled on a simpler solution. Though I love the "She Loves Me" set and photos I think this is what we are going with. A downstage set of flats that run from backstage right to about 12' onstage will be painted as the exterior of Green Gables. Behind that we will preset the interior furnisings for the scene. As that flat is slid/rolled offstage another bank of flats painted as the interior wall will rollout from backstage upstage of the furnishings. This wall will be finished on either end so that it can roll completely onstage and even downstage as needed for later interiors.  But that brings me to a new question. I have seen a couple of freestanding walls but I am wondering if I will be better off attaching this to a narrow wagon, even 2'-3' so that if I run into issues with it being top heavy I can weight and brace the wall from the back side. I hope that makes sense. I have a lovely image that I haven't figured out how to upload yet.