I've tried searching for the info using the "search" function in the forums but to no avail. I keep getting volumes of irrelevant hits...so I thought it would be better to just ask for help

So...I'm building a foamie teardrop to pull behind my 1962 Vespa scooter.
The challenge I'm facing is WEIGHT. I'm trying hard to keep the entire 40"W x 8'L trailer to a mere 125lbs. I'm on target so far with an aluminum frame and other weight saving measures.
I need a very simple, light weight method of attaching the rear galley hatch and making it water resistant. Can you guys show me some photos of your homemade galley hatch? I need a super simple, lightweight solution to seal the hatch when it's closed. I can't rely on a lot of pressure bc the side walls and are only 1" foam. Any ideas or advice? I do better with photos to figure things out so I'm hoping for a bunch of great photos of your DIY hatches and seals!
I've included a few photos of the galley area.