It was slightly (about 2 inches) wider than the existing door frame, so I had to shave off about an inch on either side using a circular saw.
Now that I say careful measurements, and look at the photo, it's obvious that the window isn't exactly centered, and that the door must have been modified before. I was under the assumption that the door had never been altered, which is stupid on my part. What this means is that I've cut off space from both sides, making it impossible to add a doorknob (working at least, since the hole would hit the corner of the glass), when I could have just cut it from the hinge side, or at least the majority of it.
This shot is not quite so bad. It might just be that the original frame is not quite correct. I'll have to measure the two sides before I get too mad at myself.
Solid core also means that it is made of pieces of solid wood, so I had to putty in the joints that became exposed through the process:
Once sanded & painted, it'll look like a solid end piece. Also in this photo, you can see the shelves I added to the bookcase under the peninsula in the kitchen for Becky's cookbooks.
As with all these projects, I learn something new every time, and no matter how frustrating they may be, I just have to remember this mistake and use it to my advantage in the future.
Till next time!
-Derek