Any of the internet sources will work not connected to the rooftop antenna (hulu, netflicks, etc...)
If you want to watch the local channels (in particular local news), you need to connect to the antenna or find if they let you watch online.
As far as regular TV shows, you need to find the service (hulu, netflicks, etc...) that carries the shows you want to watch.
Since it's rare for an RV not to have a built in antenna, why not just connect and watch what you like off the air and supplement with wifi shows that aren't easy to catch off the air.