Challenge completed! 
Wow, that was intense! 58 is my final level of gear. I could maaaybe cut one level off, but I doubt I’d be able to go lower.
I set out to use these items, and was actually able to deliver on most of them. I couldn’t get the explosive setup, that I’d planned for initially, to work, so I gave up on that. and went for a Power Toast for most of the challenge. Badaboom was out, and Topnea was in. I was probably doing something really wrong at the start, but… it worked out OK eventually. Towards the end, I switched to a Blood Blister.
I thought the Hail would be my go-to gun on the big boys, but I wasn’t able to use it as intended. Only time it came in handy was on Saturn. I got wise, and brought a Bee for this (and a respec, ofc), but it still used up my whole ammo pool on AR & SMG ammo.
I have also learned to have a healthy respect for Constructors. Normally, I take them out before they get a chance to start with their bullshirt. That wasn’t exactly the case on this run! They are, by far, the absolute worst enemies on a challenge like this. The BAC up at Control Core Angel killed me so many times, that I was ready to throw in the towel. But eventually, it just ceased all activity. Dunno if it glitched, or if it simply had structed all the bots it was set out to struct. Anyway… It finally died!
BNK-3R wasn’t to much of a challenge, really. Plenty of loaders to keep Blood Bath active.
Sawtooth Cauldron was INTENSE! The ambush at the elevator and Cramfist’s Foundry… Oh, man! So much fun! And then it was time for Hero’s Pass. 
What about those Constructors?
It turned out to be something of a cakewalk. Or at least cake-run-like-a-little-girl. I stood my ground, and took out all the enemies up to the gate where Mordecai and Brick crash their barge. Then I dunked my filthy body in the nearest oil barrel, and ran, squeling like a greased pig, all the way to the Vault gate. 
The badassery, huh! The BAC landed just behind me, as I slid towards the gate.
A nice bonus in the Vault was that my FotFH kept killing rakk, so I had Blood Bath active more or less the whole time. It was over in 4-5 cycles.
Yes! That was a whole lot of long winded old coot gibberish, so I’ll try to do a brief summary. The enemies that I was expecting to cause the most difficulties for me, turned out to be fairly easy, and vice versa. Captain Flynt was a real jerk, and the constructors were just a royal pain. Apart from the constant healing from novas, activating Blood Bath was the key to everything. The guns I had weren’t strong enough to sustain me until that first kill, so 2-3 fastballs to get things started was pretty much standard tactics.
Getting the job done with level 50 gear is impressive!