I had the Penguin 13,500 btu installed on my last trailer, 24' Tradewind. The factory said it was prewired, we searched and it wasn't. Unfortunately the installer just wired it into a circuit that had outlets and other stuff on it. On the '67 and maybe yours, there's aluminum wiring. The installer did not use the proper Aluminum to Copper connectors and anti oxidant coating. I liked the Penguin, low profile, low power needs. Ended up having a friend help run a dedicated circuit with it's own breaker box. Make sure you check all your connections if you have aluminum wiring. There's web sites you can hit on how to.
"would you rather have a mansion full of money or a trailer full of love?"