I have mounted HAM ANTENNA WHIP MOUNTS on both sides of the 5th wheel roof where I could drill a hole into the inside of a ceiling mounted cabinet. This allowed me to route my RG cables with messing with the roof.
Never had any luck finding anyone to talk to in RV CB world. Only thing we would hear was the truckers...

Inside my 5th wheel I used the heck out of the ceiling air conditioner ducks to route RG cables from one end of the trailer to the other. There are a/c ducts every 6 feet or so down the ceiling so I could fish RG cable from port to port. I have ceiling mounted cabinets on both ends of my trailer so gives me working space to bring out the RG cables. Nothing is visible anywhere... Any damage to ceiling ducts was patched with spray foam sealant. A/C works the same as before.
Roy Ken