local channels for NFL. For BYUTV (and many other channels) I also have an antenna/HDHomeRun for local OTA channels. Those I can access via Plex from anywhere in the world. That doesn't do you too much good outside of Utah for BYUTV.
I can't comment on accessing YTTV Library (DVR) channels from outside US as I have not yet had occasion to try it. I would assume that is a No unless you have a good VPN. Not sure how well VPN works with YTTV.