Thank you for the information. I've today acquired a little paperwork on what I am slowing learning to call the trailer (instead of the caravan!)
It was bought by its previous owner in Peru, Indiana. The Indiana Certificate of Title gives the year as 1954
, but that will of course just be a reflection of what was said to its issuers. To my mind, it can't be earlier than 1949, as that's when Silver Streak was founded (if I have my facts right). Given your thoughts re. the windows, that would suggest that it's maybe 1949 or 1950. Further mystery.
Yes, it will be a heck of a challenge, but I'm looking forward to learning some new skills.