My window solution worked.  Just hope that it holds up.  I cut the window film to show the pattern I wanted, then fit the pieces between the backing I'd made and the window carved into the wall. 
Here's how it looks on the interior - -

the first picture shows the template I made with the film behind it and the second picture shows the way it looks on the exterior.

Not bad.

Set up the Castle Keep project on the patio table because there's just no work space in my craft room.  The kit is heavy and awkward.

The ladders, ceiling beams & braces are all stained.  Made & stained 2 railings for stair openings.

I think I solved the problem of disguising the application of the Gothic window film.  

This is how the finished window is supposed to look. 

I made a template of the back out of a very thin ply and painted it with the stone-paint.  I'll put the film between the window and the template and hope it works out.

   

Castle Keep temporarily put together.  Trying out some of the furnishings to see how they fit.  Still lots of painting, gluing, and detailing to do.

in the process of making a corner that looks like Vermeer's MILKMAID with a doll made by Lucie Winsky

Somehow I got fixated on having a Medieval tower but have finally given up on my grand idea of creating one from scratch.  Grand plans hampered by minimal skills and a lack of things like a table saw and proper tools.

So I just ordered the 11th century Norman Tower kit from Earth & Tree Miniatures.  Now I just have to figure out how to finish it.

Trying to figure out how to build a castle tower to house all of my Medieval minis.  It's frustrating.  I either need to buy one of those miniature showcases OR stop buying anything Medieval/Tudor.  Nuts!

I've never wanted a BIG dollhouse of any era.  But a castle, that's a different story.  It would need to be 'early Medieval', not fancy.

 

Playing with the interior of porch cottage