I've been hard at work this weekend completing the first side piece. It came out just as I had planned it. Below I've got a picture of it propped up against the interior structure, with the control panel sitting where it will go in the final installation.

The second side should be easy to cut. My plan is to set the finished side on a 4'x8' sheet of plywood and then trace around it. I'll then rough-cut just outside of those lines using my circular saw and jigsaw. Then I'll use a pattern cutting bit in my router to use the first side as a template to cut the second side to exactly the same dimensions. This level of precision isn't really needed, but it make cutting the second side way faster since I can be a little sloppier on the initial cuts. Or at least that's my theory...