Buried Tweasure

Buried Tweasure:
Maru sends you to pick up an Ancient Treasure Note, located in the Ruins of Uldum, which is in the Valley of Watchers.

/way #71 37.61, 84.12 Ancient Treasure Note 1

Nearby, you'll see two Ancient Toys which give you coordinates to go to. These are optional, as you can just skip ahead to the next note for actual % completed. Some people like using the Thinking Cap, though.

/way #71 37.28, 82.92 Ancient Toy 1
/way #71 37.38, 82.75 Ancient Toy 2

They lead you to the northeast, and you'll find another Ancient Treasure Note next to a rock.

/way #71 47.51, 56.49 Ancient Treasure Note 2

Head to Zul'Farrak, outside of the instance, and find another Ancient Treasure Note next to the wall. You'll need to have your torch out for this one.

/way #71 38.84, 22.11 Ancient Treasure Note 3

This last note has you headed to Gadgetzan, and you'll find the "mysterious traveler", Yennu, in the Inn.

/way #71 52.69, 26.86 Yennu

Return to Maru for the reward!

Note: Technically, the note given to you by Maru is treasure note 1, but since you find the others, I've labeled them as 1, 2, etc.
Another Note: Unfortunately, you can't just skip to Yennu and get credit, nor is it possible to skip certain notes. You have to find all of the Ancient Treasure Notes first. I tested it out to try and shortcut it, but they won't give the quest interaction until you've found ALL of the other notes.
Another, Another Note: Someone in-game said they were having a phasing issue. If you had accepted the quest from Nozdormu in Dragonflight that used that area, but hadn't completed it yet, you'll have to complete the quest with Nozdormu, Eternus, and her sister before the Note will show up.

Just waypoints:
/way #71 37.61, 84.12 Ancient Treasure Note 1
/way #71 47.51, 56.49 Ancient Treasure Note 2
/way #71 38.84, 22.11 Ancient Treasure Note 3
/way #71 52.69, 26.86 Yennu

Ruins of Uldum is in Tanaris, not Uldum. Just using Tom Tom coords noted above sends you to Uldum. The entrance (as noted by Aztecia) is at 37, 79 in Tanaris. So dont enter the coords while in Uldum the zone like a dummy I know (very well). Do that in Tanaris and save your ego a hard hit. ^^

For Ancient Treasure note 1 - it's inside, don't stare blankly at the sand for 5 minutes like I did. The entrance is approximately /way 37, 79