Having finished up the massive chore that is Steamwheedle rep, I have turned my attentions to Darkmoon Faire and Ravenholdt. DMF definitely seems to be the more painful of the two, what with the high cost of materials (particularly the most in-demand herbs and Northrend cards) and the unpredictable drop-rate of cards.
I made myself a very elaborate spreadsheet to keep track of what cards I have and answer various questions about rep and pricing. Some of the sections came specifically at the request of my fellow Insane guildie. You can check out the spreadsheet here. If you have a gmail account, you can easily use that to log into the zoho site and save a copy to input your own values.
At the moment, my method is searching the AH and buying up any reasonably-priced cards (cheap decks are a pipe dream, sadly), then searching for motes/Primals of Life. I have decided to farm Outland herbs (a few mobs in particular). I get the feeling that I need to expand my purchases to everything falling under the price ranges I so helpfully worked out for myself, but for the moment I don`t have the addon to facilitate those searches, nor the gold resources willing to be spent.
The closer I get to the end, the faster I want to be doe, but considering how long I`ve had this in progress (I won`t say "working on" because I have taken many breaks), I can wait a bit longer. Especially when I`ve got a million other projects (see [Cata] Bucket List above) in the works. And although I have the heart of a grinder, I have been known to grind out other reps to avoid working on more cumbersome tasks. Just last night I found myself in UBRS trying for the Wildheart chestpiece instead of farming Primals!