Might be overkill, but here's an example of the level of detail of the work I'm doing:
This piece goes under the windowsill. It's just a piece of the casing that runs up the sides of the windows and door, but flipped so the thick edge butts up against the bottom of the sill. I mitered some side pieces for a more finished look than just straight-cut ends.
Shots of one window, before and after casing install:
18 pieces up, 54 to go.