I started a blog to document my journey restoring my 1962 Shasta compact. I will post as much information as I can find that has helped me along the way including but not limited to tools I used, mistakes I've made and any outside sources with helpful information I have found. I already posted a thread on RV moisture prevention. The information therein was found over 1 1/2 yrs. ago and the main link no longer works. I'm glad I had saved the information on my computer though. It has a lot of advice I personally don't know how good the advice is since I'm a novice and in no way an expert. I hope you find it useful
What a fun story! You were ondering about the "vent". I doubt it is original to the trailer. There's really nothing there to vent. THe stove/oven combos of the time were not vented )that didn't happen until the next generation of Compact), and they would have vented up anyway. You have an icebox (no fridge), so its not that, either. My best guess is that there was a tear or a hole in the skin and they put a "decorative" vent cover over the flaw to disguise it. It happened fairly frequently, actually. The skins are pretty thin, and if something hits it just right, it'll tear or puncture.
Glad you have been able to use it already. When we went to pick up Hamlet, we'd never seen one except in the EBay ad. The seller had several other Shastas in a large metal barn/workshop that were all larger. We liked the layout of the Compact best of all and have never regretted that we didn't get a larger model. He works for us (and our granddaughters).