Frank, hopefully someone with your model of Cedar Creek can give you an exact answer, but I'll try in the meantime.
If you don't have a switch box to control what the input is to your TV, the you have a wall plate that looks like this:
The coax that connects to the TV is going to be connected to that switch plate, so hopefully you can just follow the coax wire from the TV. When the little black button on that is pushed in (green light on) then you have off-the-air TV. When it's out/off, the "Cable" input on the outside of the RV will be connected to the TV. Because you have to switch it between the two, it's not something that you will have to remove the TV to get to.
And no, there are no wiring or plumbing diagrams available. We all wish they were.