Welcome to the forum, Jennifer!
Glad to hear your son was not seriously hurt. It does sound like yours was built as a front bath model. Some had only a toilet, and some were left empty as a privacy closet for a porta-potty. In your case the partition was removed by a PO and a homemade bunk substituted.
Surprisingly, even the factory bunk set-up lacks any kind of safety rail. That was the first thing I added. You can see what I did if you click the "Registry" link under my profile at the left.
Since yours is a custom set-up, it's hard to advise on how to add a safety rail. If you post a picture of what you've got, I'm sure you'll get some great ideas. See post #7 in the thread Forums 101
for how to add pictures.
The large front window on non-bath Scamps is fixed plexiglass. Installing a large operable window on the front of a Scamp
is difficult because of the curvature. Operable windows
require a flat mounting surface, so fiberglass work would be required.
An alternative solution to increase ventilation would be a 12V Fantastic Fan in the roof. Combined with the small tip-out window, that should create some airflow in front. Light
is another matter... We do enjoy the view from the big front window during the day (ventilation comes from the screen door). At night we put up the rock guard to darken the trailer. A 12V roof vent is on my wish list...
Enjoy your "new" Scamp!