I finally decided to do something about it. For several years, I thought about cutting a hole in the outside of the camper and installing a door. So, a few days ago, I got around to ordering a door. I did my best to take some measurements to figure out what size door would work the best and found that a 14 X 18 inch door would work the best. I took some more measurements to try and center the door front to back in the compartment. I then drilled a hole from the inside where I wanted one of the corners to be and then went outside to mark out the size of the hole. I marked it all out with tape, made some more measurements and then, with great trepidation, started cutting into the side of the camper.
Below, you will see the results of that cut. As you can see, the door to access this from the inside is very small compared to the size of the compartment.
The next step was to frame in the opening by inserting wood all the way around the opening. I didn't need to do much across the top, but the rest of it all need to be framed in. As can be seen below, I am all set up to cut some wood and frame it in. I used some scrap 2X2 I had laying around the garage, because the space between the inside wall and outside wall was 1 1/2 inches. After cutting to the correct length, I then used my air stapler to attach the wood, both outside and inside.
After getting it framed in, I then cleaned up the inside of the compartment. Since it never saw any use, it was full of spider webs and a lot of dust and such on the floor. Below, you can see the hole all framed in and the compartment all cleaned up.
The next step was to install the door. Below, you can see the door laying on my portable workbench. I had to run some caulking tape all the way around the edge before I could install the door. After doing that, I then installed the door and screwed it down with my battery powered drill/driver.