For the glass, I found some old microscope slides, did some research on the web, and developed my technique. There's photos below - but basically I purchased a diamond-tipped scriber from Amazon, and create the windows by first scribbing the slides firmly with a straight edge:
To make the break, it works better (some surface tension issue with the glass) to do it underwater. I just used a little container and a small piece of dowelrod. Put the rod under the scribbed line, then press gently on either side to make the break:
Here's what I used, but microscope covers (as opposed to slides) are much thinner and probably easier to work with. But, I already had these handy...
To install the mullions, I found it easier to apply them to the glass first, then put the glass onto the back of the wall.
The final look - nice reflections!
So - for Mancos I needed (operationally) a mine of some sort. The layout doesn't have room for the prototypical scene (although coal mining did exist near Mancos). So - and I think this is the only completely non-prototypical section on the layout - I decided to use Campbell's supply warehouse and Silver Spur mine (both kits I had on my shelf) and build a mine warehouse and the mine itself.
Here's the warehouse. For this buiding, I used roofing from Wild West Models instead of the Campbell shingles. They worked well! Rusty Stumps has some nice actual cedar-wood shingles which I might try in the future.
And here's the mine itself - all stock Campbell except the windows:
Hmm - um, not sure how this happened - time warp maybe? :-)