Root Method for Nexus Player that ACTUALLY Works?

Hello,
So I have been trying to root my Nexus Player with absolutely no luck at all!
I am following this method to a T!!!!
http://cord-cutters.wonderhowto.com/...layer-0160218/

Long story short, everything goes great and the Nexus Player re-boots. I go into the SuperSU App and the Installation Fails. Then, when I reboot, I get stuck in the boot animation. Only way out is to restart Nexus Player holding the button on the bottom, and re-running the "fastboot boot root.img" again. But, the same thing just happens over and over and over. "Installation Failed". This is pretty much my first time rooting an android device and it is being a serious pain in my ass! I did root my LG G Pad F7.0 and that was a cake walk. I thought Nexus Devices were "THE BEST" and "easiest" devices to root, blah blah blah. Well, not for me!

Can someone guide me to a root method that actually works? That would be greatly appreciated. Thank You!

Info:
Nexus Player
Version 5.1.1
Build LMY48N

I really want to install CM12.1! I bought a Logitech K400 Keyboard so I can use the Trebuchet Launcher properly.