The Lunar Festival can be the most tedious of the Seasonal World Events due to the traveling all around the world aspect and the countless hours spent to find all the Elders. It does have its rewards, nevertheless. Take in mind you will get reputation with the Horde or the Alliance, which translates in equal reputation for all the races of your faction. No need to spend weeks in Alterac Valley to increase your reputation with a specific race.
The best reward to completing all the achievements of the Lunar Festival comes once you complete all the seasonal world event achievements: a Violet Proto-Drake, which increases flying speed by 310%.
There are a few elusive Elders that are placed in inconvenient and misleading locations. For example, you are told to find Elder Moonstrike at Scholomance. Don’t even bother to enter the dungeon. She is found outdoors by walking upstairs to the roof of the Scholomance building. Elder Starglade is outside Zul’Gurub. Elder Mistwalker is not inside Dire Maul, you can find him in the arena. This one in particular can be dangerous if you aren’t into PvP as you get auto-flagged. A rogue could be awaiting to gank you with a grin on his face.
Elder Meadowrun is supposed to be at the Weeping Cavern in Western Plaguelands. He is not even inside it or near it. You will find him near the main road far south of the Weeping Cavern at coordinates [65-47].
The Stratholme elder can be found at the Festival Lane. Enter through the main gate and take the route to your right. One of the Northrend dungeon Elders, Elder Ohanzee, can be deceiving. This is the only Northrend Elder that requires you to run an Heroic Gundrak. Enter throuogh the backdoor zone-in to reach the Mamm’toth prophet. The Elder Ohanzee may be found near Eck the Ferocious, who is accessible only in Heroic-mode after killing Moorabi.
You may find other Elders by visiting the Lunar Festival Guide. It tells you where to find them by coordinates. The Northrend Elders have been added. Feel free to update the Worldofwar.net Wiki.