Overall, this was kind of a non-grind. I'd initially expected that I'd end up having to run Molten Core over and over to get the Fiery Cores and Lava Cores she'd need to turn in for rep. Then I realized that - for whatever reason - I could usually find Fiery Cores on the AH for 60-90 gold each. Lava Cores were about 200g each, and Blood of the Mountain 400 gold each... but by being patient, and buying a lot of cheap cores, I managed to get her rep up to about 18k fairly cheaply. (Oh, OK. I did splurge 1500 gold for a stack of lava cores at one point).
Add in some random Dark Iron Ore turn ins, including the last one, and getting to exalted was pretty much just a matter of spending money as fast as I could make it. Let's face it, too - at 80, in a lot of cases, it's quicker and easier to make 500 gold and buy 5 Fiery Cores of the AH than it is to actually farm those cores yourself. The Zandalar Tribe rep grind was much the same, in that you could actually get to exalted without setting foot in Zul'gurub if you really wanted to for some reason. Nice breaks from the usual "run this dungeon 20 times and then we'll like you" type rep grinds, but not nearly as fun.