If the RV is on a permanent site and you're not planning to move it regularly, I'd mount the new antenna on a post or steel mount beside the RV, run the coax through a "coax passthrough" to connect to the TV. This would completlely bypass the KEYTV system. You "could" uf you want, use the cables at the back of the KEYTV box and connect directly to the TRAILER coax system, bypassing the KEYTV box.
I would, if it's a permanent wiring system, bypass KEYTV. It's in its infancy, not yet a reliable system and subject to significant limitations and failures.
Here is a photo of one type of passthrough and a link to describe it:
https://www.amazon.com/JR-Products-4...a-491662267409