I would finish Normal-Nightmare-Hell playthru with trapper or mind blast.
But once Hell Baal is dead you can respec to PS.
From there you can quickly farm Pit, Eldritch, Shenk (or any easier lvl 85 zone, like Catacombs).
Arcane Sanctuary is ez too.
Actually I liked AS runs more with the PS than with the lightning trapper.
Cows are doable too, just need to be little careful.
Can hire A3 cold merc for Blizzard aoe slow/damage.
(get Harmony bow on weapon swap to go faster around)
A1 merc w/Pus Spitter is also nice.
Was doing some easier T1 maps with A1 merc.
Crescent Moon is pretty good early runeword if you are lucky to find +PS base.
Or shop Anya for +MA/PS claw.
If you can't find some cheap Stromshield then can craft safety shields for early game.
Craft Hit-power amulets for AR boost.