[rasz]

Its trivial on the desktop with one of the extensions/userscripts, both hiding suggestions and autoplaying what you select.

[fma]

Yes, actually you can do it on a computer easily. You can even use like ListenOnRepeat.com and control the playlist. The problem is when she opens her retail location she wants to do it from the app on the tv, or app on her phone and do a Chromecast.

I'd rather not install a computer there just to show some videos...and I don't know why YouTube forces the suggested videos to paying customers without giving an option to turn it off.