[SCH-I545 4.3 MK2] Custom Recovery, Nandroid, stock update, Custom ROM?

I have a Verizon Samsung Galaxy S4 in the United States (SCH-I545). I'm rooted on stock 4.3 (I5455VRUEMK2). I did this a long time ago, and don't recall which Root kit method I used.
Installed: SuperSU v2.01, Terminal Emulator 1.0.70, SQLite Editor 2.11. I do NOT have a custom recovery.
First goal: I want to install a custom recovery and do a Nandroid-type backup before taking any other steps. From what I am reading though, because I have 4.3/MK2 I can't install TWRP. What options do I have?

With a custom recovery in place, I would do a FULL backup before I would update to (or flash) a newer factory 5.x ROM. (I don't even know what current stock ROM version is (:o). I disabled the factory OTA notification service but I don't recall how I did that -- I think I used Titanium to Freeze one more apps?

Next I would want to root the (newer) stock ROM. Will I need to plan to update/change to appropriate Custom Recovery for newer stock ROM?

Later, I will probably try some Custom ROMs.

Basically, I am looking for a strategic outline of what steps I can take to update my phone while having flexible options going forward. My level of Android knowledge is low-ish. I don't understand a lot of the codespeak and acronyms, but I'm fairly technical and can read. :)

Thanks in advance for your guidance.