Roof antenna and internet share one indoor coax hookup

I never even imagined trying to get internet through the coax cable in an RV. I think if I was in your shoes, I'd add an additional cable port like others have mentioned. Super easy to do. The entire job should take less than 20 minutes, and cost less than $20. Many RVs have other ways to route a wire in without poking holes in the skin. Does your 30 amp cable feed into the trailer? If so, that's an easy way to get another cable inside.