How were you planning on fastening your tailgator to your mount so it wont fall of when your driving down the road? I keep mine loose so I don't have to deal with obstructions ie trees..... When the tailgator is out of the box its not that big..
For connecting to TV I would not drill into the roof. I would get one of these
http://www.shoprvparts.com/product/14505F/phone-cable-tv-inlet-plates-1-2-diameter-installation-hole-white.htmland mount it on the outside of your RV opposite your TV cabinet so it will be inside the cabinet.
Just connect cable to tailgator then to inlet plate... I would not try and run the coax in any kind of conduit, just hook it up when you get to where your going...
