Question: When I hook the cable to the RV and hook up the TV inside, the picture is bad. I can run the cable straight from the RV park connection, and have perfect picture. Any suggestions?
Answer: If you have a power booster associated with your over-the-air (aka batwing) antenna, make sure it is off. The power booster can interfere with your cable picture quality.
If that is not the source of the problem, then you probably have a bad wire or loose connection somewhere in the cable TV wiring within your RV. This is not easy to diagnose or fix, since you will have to trace all the wiring to find the issue.
You might prefer to just run the wire directly and figure out a way to bring it through a window or something. We have done that in the past, and just sealed the window opening with duct tape to prevent dust, insects and rain from getting in.