Stonetalon Mountains 18 - 18
Once you land in Sun Rock(1) grab all of the quests and head oustide to start killing spiders While you work your way to Ziz Fizziks(2). When you reach Ziz refresh your quests then head east. Kill spiders and collect the eggs around the trees for "Deepmoss Spider Eggs". When you're done in this area head further east to kill 15 Venture Co. Loggers and Venture Co. Operators(3) for "Goblin Invaders" and "Super Reaper 6000". When you're done refresh your quest at Ziz Fizziks and head south to the wanted poster for "Wanted - Besseleth"(4) Grab the quest off the wanted poster then head into Sishir Canyon. In here kill Besseleth(5) who sits in the back. Continue south to Malaka'Jin(6).
Turn in "Blood Feeders" and grab "Report to Kadrak". Continue southeast to turn in "Goblin Invaders"(7) and accept "The Elder Crone" but ignore the other quest. Next up, head to "Boulderslide Ravine"(8). Here you have to collect 10 crystals and explore the room with the water in it. If you get all 10 crystals before reaching the room, just kamakazi up to it and spirit rez. Once you're done continue back to town. In town turn in your quests then fly to Camp T and speak with Jorn for the followup. Also Grab "Tribes At War" from the Imprisoned Quilboar.
The Barrens 18 - 19
Next up "Consumed by Hatred" Head to the quilboars and kill them until you have 
60 Quilboar Tusks. Also kill the Stormsnouts and Thunderheads for "Chens Empty Keg". Return to Camp T and fly to Ratchet to turn in your two quests. Accept the followup then fly to XR and turn in your quest. Continue north to turn in "Nugget Slugs" and proceed into Ashenvale.
Ashenvale 19 - 20
Grab the Splintertree(2) flightpath then head to the western side of the zone to Zoram'gar Outpost(4). Accept the quests here and turn in the ones you got. Then head north and start killing Nagas for their heads. Return to town when you have all 20 heads and grab "Vorsha the Lasher"(5). Protect Muglash until he gets to the camp fire. Extinguish it and fight off the waves of nagas. Kill Vorsha and return to town and turn it in.