For an older TV (with a HDMI input on it), get a Google Chromecast or similar. With the YoutubeTV app on your smartphone, dial up a show and then cast that to your TV. Easy. Your smartphone becomes your TV remote, in other words. We did that until recently buying a new smart TV.
On a laptop, I just login to Youtube TV's website and watch away.
We've had YoutubeTV for a year or so now, and it is flawless. The DVR setup is great, as you get every episode of a specific show, no matter what channel it is broadcast on.