Dusting off the Nexus 7. Where to begin.. Im already on a custom rom and rooted, but.

Hey guys, just pulled my nexus 7 out. I want to update it to the latest, but it's been so long since I've used it, I don't know where to begin. Right now here's what it's running:

Android 4.3
Model ME370T
Build CleanROM 4.0.0
Kernel 3.1.10 leankernel grouper 43-2-0-+

Whatever I do, I don't want to lose root etc. I would like to update it to either the latest kitkat if available or Lollipop. Have all the bugs been worked out for the most part with the lollipop roms on this tablet? I've only briefed the threads so far.

Should I just use Wug's Nexus Rootkit to do everything? I just don't want to lose root. I know with my ATT s4 you can lock the bootloader with the later updates and just dont wanna make a mistake.

Trying to keep the tablet as close to stock look as possible, but some cosmetic changes aren't too big a deal to me. Cleanrom was pretty good, but I'll have to research some of the new ones now.

Thanks!