Buy one of these and using a spliter feed the tv and hook output to coach cable outlet. To be clear I'm saying to plug it into where the tv normally gets tv ant.
That should distribute it to the others.
If that doesn't work you'll need to hook the output into the inlet line on the outside of the coach.
You might also look behind the outlet with the ant booster is since that is normally where the main splitter for all tv's is. You could tie in there.
Google search for: RF Modulator RCA -> COAX Converter