Trailer Inspection Checklist
Sorry - looked on the app...didn't see it there. I've attempted to upload a pdf file of it to look at. Hope that helps. There are also a number of inspectors in LA, but not sure they are near you.
If you have leaky vents, then number one on my list would be to check the floor for soundness. Take a screwdriver and probe the perimeter for soft spots. The floor is the most important thing that holds the trailer together. If you have floor rot, especially in the back (if you have rear bath), then you are looking at extensive repairs...as floor rot leads to separation of frame and shell and suggests frame damage.
If you are going to tow some distance, check the axels and obviously, the tires. If it is sitting low on top of the tires, then the axels are suspect.
Make it safe first. Tires, Axels, Brakes, Running Lights
When you get it home, you can start to look at systems like LPG: Check for damaged gas lines due to freezing or other damage.
If it has a Univolt Converter, plan on replacing it with a 3-stage converter....it will boil your batteries.
Check your water lines for evidence of freezing or leaking.
After you check safety related systems, plan on spending some time sealing up any potential and/or obvious leaks...like the vents. You want to prevent any further damage until you can decide your eventual game plan.
Take lots of pics and post them. Pics help Forum members help you.