Gents and possible ladies.
First, thank you all for the help.
Second, I claim victory to this round of skoolie battles.
I tried cardboard and had a hard time but, thin paper not much unlike butcher paper worked perfectly.
Mudda, first thank you for responding. I have watched your videos up to the lift series. Naturally, I should have paid closer attention to newer videos. For that, I am sorry and thank you for the work you do and videos you make. You do great work and have helped me along the way more than you could know.
Here are the end results.
The next step is to find a window to put in the opening.
I added more structural bracing as well. I am going to double up and over lap a few sheets on the interior as well to try replicate the original design.