I also went ahead and lined the inside with cork. O how I just love a nice (analog) pinning surface. Here's how it all went down:
First I removed these scary looking hinges from the door. These things are actually inset into the door.
Best practice is to prop the door while removing hardware and use a jar to hold all the screws.
I used the back-side of wrapping paper to make a template for cutting the cork.
I have a very large roll of cork in my garage. It is actually a very useful thing to have on hand. Mostly I've used it to line the drawers in my kitchen (looks good and works great) and to make custom sized cork boards for other workspaces.
Cut down to the exact size after glueing sheets together.
And as you can see, I also did all this before I painted for fear of damaging the painted surface during this glue up process.