The first thing you will need is a nice tranquilizer to settle your nerves. Punching a hole in your roof is a stressful ordeal.
I had to do it to my 2017 Greyhawk to get my Direct TV cables in. I had my son on the roof while I was inside. We punched the hole into a cabinet above the entry door. There were many cables already in the area behind the cabinet side wall so we just added a few more.
We used the cable cover that came with the install kit and used a lot of silicone sealant after cleaning everything with alcohol. Got the best sealant I could from Home Depot as I didn't want to cheap out here.
After over a year of use and a lot of rain storms, everything is still good. It should last many years before the silicone would need to be replaced.
Picture has arrows showing cable runs. The rear cables were for my solar panels which were run in through the fridge vent. No holes drilled there.