Running Ethernet cable in a Raptor

[mj5150]

The garage of our Raptor is going to serve as the home office for the wife and I. We both work from home and have tech/IT jobs.
I plan to remove the TV in the garage and install a shelf for the cable modem and our networking equipment. I'll use that coax connection for the modem.

Question.....has anyone run CAT5 in their RV?
I need to run CAT5 (Ethernet cable) from the TV in the garage to the TV in the entertainment center for our Roku which I prefer not to use wirelessly.
I've never owned an RV before, so I am not crazy about drilling holes through walls and fishing it around that way.
The service guys at my Camping World (where we bought the Raptor) suggested running through the underbelly. They quoted me about six hours worth of work, and about $900.
They told me running though the ceiling/roof would be far too complicated and involve removing lights and fans.
The tech was actually cool about it and took me out to another Keystone RV and showed me the thin plastic sheeting that he said goes all along the underside, which I would have to remove. He said as you remove it, often the small screws Keystone uses break or strip out, so they end up having to drill new holes and use a more robust screw.

If it really is this complicated, maybe I'll just poke the cable through a small hole in the window, down the outside of the RV, then poke back in through a small hole by the entertainment center. Not aesthetically desirable, but also not $900.

Your thoughts, opinions?
Should this thread be in the Technical Corner forum?

-Mike