Hi Rick,
The exterior cable TV coax connector meets and is combined with the rooftop antenna coax at the signal booster. The output of the signal booster typically goes to the living room entertainment center and to the bedroom if you have a coax connection there. On some rigs there may also be a coax outlet in the basement, and on some models, there's a connection for an exterior TV. Routing can vary, but starts at the signal booster location. If that's in the bedroom, the coax goes from there to the basement and exterior TV locations (if you have them), and then to the living room.
To watch cable, the signal booster must be OFF. To watch antenna TV, the signal booster must be ON. In addition, on the TV menu, most TVs require you to select either cable or antenna, and to do a channel scan.
Not every trailer comes with satellite pre-wiring. If you don't see an external coax connector marked satellite, you probably don't have it and would have to either run a coax cable through a wall, or use a flat jumper and go through a window.