Everybody starts off hostile with the Timbermaw - they don't like anyone. Make sure you turn off the "at war" check box in your reputation page, though.
There are three sets of repeatable quests for Timbermaw rep. One is in the Southwest, given by a Furbolg standing on the left side of the road just past the Enerald Sanctuary, and involves killing a lot of Deadwood Furbolgs, six each of Gardeners, Warriors, and Scouts. You get 5 rep apiece per kill, plus more for repeating the quest.
Then when you reach unfriendly (I believe) and can run through the Timbermaw hold without being attacked, there is a questgiver on each side of the tunnel, one in Felwood and one in Winterspring. Each has a repeatable quest for drops off the Furbolgs in their respective zones, the Winterfall furbolgs in Winterspring and the Felpaw furbolgs in Felwood.
For the Thorium Brotherhood, you're going to spend a lot of time farming Incendosaur scales to get to friendly, then Dark Iron Residue (drops in BRD from almost everything) to get to honored, then Dark Iron Ore, Blood of the Mountain, or some other rare drops to get to Revered. Be ready to grind or pay, and the trips to BRD are required once you're at honored. The quest turn in after that, as LockeCole says, is inside the instance, and not all that close to the beginning either. Of course, the same guy sells the recipes you want anyway, so you'd have to go in regardless.