Windows were purchased from a local surplus RV parts warehouse. The cutouts from the doors were mounted on frames and then the interior and exterior plywood were routed for the windows. The door frames probably could have been solid but continuing to use the 1x2 meant there was room for rigid foam. Not wanting to miss an opportunity (and having plenty of foam scraps lying around), even the corners of the frames were filled with little scraps. Now I just need to remember where the frame is when I attach the door hardware.