Currently running an attempt at a mutated gunslinger, picking up teleport and multiple legs for maneuvering around and kiting enemies. To get rid of the rest of the mutation points, I picked up kindle and nightvision, which have been a bit underwhelming. Nightvision is nice but I figure I could have gone for fur or something and just used a glowsphere in my offhand, but I suppose it's nice to have a secondary weapon for melee. It was also nice in the early game when I was yearning for more slugs, but that problem was solved once I got to Grit Gate and bought all the slugs from the entry merchant, since he seems to always carry around a thousand.
My character feels pretty good right about now. Leveled up multiple legs gives great movespeed, which when combined with constant pistol barrage is surprisingly effective. I was very hesitant to do Golgotha since I felt a bit under-leveled (I was about level 10 when I entered), but I decided to just sprint through the vents instead of getting caught up fighting a flood of chutecrabs and gells. The Slog fight felt tense but I realized it couldn't really catch me, so in the end it was a done deal. I did end up getting Glotrot (for the first time actually... it's super annoying), and come to think of it kindle did help me light a canteen on fire to help cure the Glotrot, but then again I could have just used a campfire. I also used it for clearing a few paths through the Golgotha ooze, so overall kindle definitely seems like a mutation that rewards creative use. I still mostly just use it as a mediocre, close-range version of clairvoyance, though.
As for now, I'm gearing up to do Bethesda Susa, which I've never done before. I figure I should aim for at least 25+ cold resist, but who knows. It's interesting to debate which current equipment I have is worth sacrificing for cold resist, but it seems like this mostly depends on what you find. Nevertheless, I'm going to focus on tinkering to hopefully get an upgrade to my borderlands pistols, and also try to get weathered from the endurance tree for Bethesda. Seems like it's time to farm the caves a bit.
Edit/Update: Just electrified my pistols, and I think that elemental mods, or at least the electrical mod, is bugged and not working on borderlands pistols. Unless it's simply reporting the extra damage as normal damage, but I'm unsure.