RV wiring has changed over the years as has the wiring coming from satellite receivers. New receivers are wired with an HDMI cable to the TV. RV manufacturers have generally not run HDMI around the units. This means you'll need a separate receiver at each TV (unless you want to run your own HDMI cable or a wireless version).
It is possible that one of the outside connections runs from "Sat Prep" to an outlet at your main TV, while the other runs to an outlet in the bedroom. You should be about to test where the external connections run with an ohm meter and temporarily connecting the center conductor to the braid.
If the connections run to the right places you won't need to run more wires. By using an appropriate splitter before the satellite receiver in the living room and connecting that through the wiring to "Sat Prep", then connecting that to connection going to the bedroom, you could then use a second receiver there.
If all this sounds like Greek, you'll probably need some local help figuring this out.