Interesting post.... well I recently mounted my antenna mount on my 5th wheel, using the ladder, like most I would gather. Because the horizontal part of the ladder at the top was at about 15 degree angle, I decided to use the vertical part of the ladder to be "square" (this is the engineer in me, hi). Coax comes down vertical ladder rain using zip ties. Had to take pix on the wrong side because sun was directly behind if shot from correct side, hi.
At the base of the ladder, I placed a ground strap onto the ladder since it wasnt grounded to the RV frame. Didnt have any big strap or even some large coax braid, so just used a piece of RG-58/u with the center conductor and braid shorted together at each end, then soldered on a connector. I know, it isnt KOSHER, but it does work.....sofar!
For the entrance, I ran the feedline under the trailer abit, using zip ties onto existing wiring loom and then came out next to the slider, using acouple of cable clamps screwed into side of RV body, then thread the coax through the rubber gasket on the slider into the living quarters area.
This method is "quick and clean" at the same time. XYL didnt even notice it until she moved the lounge chair, and then saw this cable. I told her it was for the Satellite, but she knew I was fooling, ha... This setup came through a rain when at the coast afew weeks back, with no water coming in, along the cable.