There are 34 rewards ranging Honored, Revered and Exalted. You gain reputation with the Cenarion Expedition by completing quests in Cenarion Post (Hellfire Peninsula), Cenarion Refuge (Zangarmarsh), and Ruuan Weald (Blade’s Edge Mountains). Additionally, killing mobs and bosses in Coilfang Reservoir dungeon wings: Slave Pens, Underbog, Steamvaults, and Lady Vashj’s Serpentshrine Caverns.
There are two repetitive quests to increase reputation with the Cenarion Expedition: The first quest only available until up to Honored 12000/12000 – Plants of Zangarmarsh, given by NPC: Lauranna Thar’well – where you have to bring to her 10 Unidentified Plants – which drop from all mobs through Zangarmarsh, or a random drop from herbing plants or herbing Fungal Giants (found at the Dead Mire and the Spawning Glen) in Zangarmarsh.
The second repetitive quest, requires gathering Coilfang Armaments which drop randomly from naga in the dungeon wing: The Steamvaults (lvl 68-70). The quest is titled: Preparing for War, by NPC: Ysiel Windsinger.