Root "Nexus 5" Android 4.4 kitkat to install custom rom? What is the best guide to root the "Nexus 5" 4.4 Kitkat version? There seem to be so many guides and I'm not sure which one is the easiest and quickest to follow.

Also when rooted, where can I get custom roms? 

Also what if I wanted to flash it back to Stock 5.2 lollipop, where do I get that?
It was actually very easy to root and flash a new rom or stock rom to it. 

First thing is rooting your device by doing the following:


Make sure your Bootloader is unlocked so u can flash a new one to it. (fastboot oem unlock)
Install JDK and Android SDK to get access to the command "fastboot"
Download the superuser.zip file to your SD card on your phone
Download the CWM (clockwork recovery) or other recovery image 
(http://www.teamandroid.com/2014/06/19/root-nexus-5-android-444-ktu84p-kitkat/2/)
Flash the recovery image to 'fastboot flash recovery asdfasdf.img'
Reboot to RECOVERY MODE and install the superuser.zip file
Flash the new rom image by getting the zip file and doing a "fastboot -w update romfile.zip"


Note: You might have to also flash the proper bootloader version and radio version or else it will throw an error. these files are usually along with the package...