I appreciate the info and the offer! I won’t be messing with the Ethernet since that’s used for networking. I was mainly looking to hook up an IP phone or something easy, but assumed I couldn’t just connect that to my network and needed something so the two phones would tie together.
Against some better judgement, I did direct burial. I did consider walkie talkies, but heard doesn’t work well in a metal barn (I confirmed I basically have zero cell reception). I could look at adding the antenna though, thats not a bad idea.