+1 to idroba. All you need to do is get a chunk of RG-6 coax with F connectors long enough to run from the park cable TV outlet to your TV and then find a gap in your Airstream big enough to snake it through. I bet there is one on your vintage trailer. Refrigerator and water heater compartments are likely places.
On our 1980 we snake a coax through a crack in the coach battery box into the trailer when we want to hook up to cable TV. The TV sits on a cabinet right next to it, so the cable inside the trailer is out of the way.
Yeah, I know, crude, rude, and socially unacceptable, but it works. . .