All cable boxes give you an HDMI output these days so the simplest way is to bring an HDMI cable from the TV you'll be using, or from a free input from your HDMI switch, and leave it where you can easily plug into the cable box.
You'll also need a coax from the cable distribution in your RV. You may need to add a splitter to get that down to the same place. To make it easier get a cable with a screw on one end and a slip connect on the other.
Put both of these in a convenient location. Now you just need to make the two connections, plus power, and your done. You'll never need to dig through the cables again. Basically it's about the same as setting up a game box that you don't want to put in the cabinet.
There are other ways to make this work much better but this is quick and easy to start.
John (N6BER), Joyce, Lucas (Golden Retriever mix), Bella (Great Pyrenees) and Lance (Great Pyrenees).