Bob I have always preferred my models to have a “lived in look” I think this will be used but well kept.
Gareth, the windows are cut from the main body which is 2 thickness’s of 0.75mm plastic (Green), giving a wall thickness of 1.5mm. Then I cut some 0,5mm card into strips that are 3mm wide. These are stuck the the edge of the window so one edge is flush with the back of the wall and the front edge projects out from the front. (Blue) Finally some Evergreen Microstrip (Yellow) is wrapped around the protruding strip.
Hopefully the picture above will explain, for clarity I haven’t included the guides that the window slides into.
I take no credit for the frame construction, my Dad has just done the same on his Narrow boat and I just copied, then took it a step further with the slide out glazing for exactly the reasons you like the idea,