I bet, if you're going to be going back to Classic WoW for achievements, especially the reputation ones, you wouldn't mind getting as many as possible. Well, good. I've finished off the important Outland reputations for the moment (mostly the pet and mount ones) and I've begun working on Timbermaw Hold and Wintersaber Reputation. These two are beautiful together, especially if you're lucky enough to pick a time when no one else is farming the Winterfall mobs you need for both.
Firstly, if you're still below neutral with Timbermaw, you should head down to the South flight point in Felwood and find Grazel. He'll give you a quest Timbermaw Ally which then leads to allowing you to gather Deadwood Headdress Feather and hand those in for reputation, and he will also send you to his friend in the North of Felwood, and you do similar quests to hand in the Deadwood Headdress Feathers to Nafien in the North. Once you're neutral, you can safely pass through Timbermaw Hold into Moonglade or Winterspring. Nafien should give you the quest to speak with Salfa, the Timbermaw NPC on the Winterspring side of the Hold. Salfa will let you hand in Winterfall Spirit Beads for a quest Beads for Salfa, after completing Winterfall Activity, given by Salfa. Just a note, once you get to Revered with Timbermaw, regular mobs no longer give rep, but still drop the rep items needed. The "bosses" of Winterfall and Deadwood give you 40 rep each though.
Ok so now that we're through the set up, you can now collect Winterfall Spirit Beads, which leads us to Wintersaber Trainers rep. If you follow the Northern road in Winterspring up to Frostsaber rock and climb up behind the rock to the top, you'll find a neutral quest giver. You'll pick up a quest called Frostsaber Provisions. You can only loot the number of items required for the quest while the quest log is in your inventory, so don't waste time. You get 250 rep per hand in. At 1500/3000 Neutral, you get another quest: Winterfall Intrusions. This sends you to the Winterfall village just north-east of Everlook. Kill the mobs required, collect beads while tidying up the quest, grab your meats for the provisions quests when travelling between the quest giver and the Winterfall village, and voila! It took me a few hours, and I went from Neutral to Honored with Wintersaber Trainers, and I'm well into Revered with Timbermaw now, although I started with friendly reputation.
This actually made the grind not so bad. I expect Honored to Revered to take one more day, and Revered to Exhalted to take 1.5-2 "days" of grinding at the pace I was working at. I cannot commit myself to 8 hours of grinding a reputation at once. I think it took me 5 hours to get as far as I did, and there was a lot of goofing around in between.\
Goodluck. Hopefully you'll get some epic BoE world drops, Darkmoon Faire cards, and don't forget to save all those bear flanks, they sell for 50g a stack on my server!