Assuming the previous owner didn't rewire, the cables installed by WRV should be color coded. They used white coax cables. There is a color band on the ends of the main coax leads. Maybe you will get lucky and find them. Otherwise you will need to follow the previous advice.
Portable satellite - Purple
Roof satellite - Green
Antenna - White
Cable - Red
To outside TV - Black
To bedroom TV - Blue
Once you identify these coax cables, you need to connect them BSM (By Some Means). A friend's coach was wired with a whole bunch of splitters, which degraded the signal to the point that they got a very weak and unusable.antenna signal. I would suggest a switch box such as the following:
Discount Mobile Video and Rear Observation Systems
(I just picked this website because it has a picture of it and the part number. Do you own search if you decide to buy one.)
This switch will take the incoming coax leads and switch them to the front TV, the bedroom TV, and the outdoor TV. It makes it petty simple. If your satellite receiver has a coax output, you can connect it to the switch AUX input and get the satellite signal to the bedroom and outside TV's as well as the cable and antenna.
If you go the other route and kidnap the Best Buy geek, be aware that he might not understand RV entertainment center wiring. It may be a little more complicated than home theater connections he is used to. But he should figure it out.
I would definitely not pay the RV tech a high price if he doesn't know what he is doing. Too often they will screw up worse than it is to start with. I have seen some of their work on friend's coaches!!!