Freeing the Meadowlands involves defeating the Exiles in the Meadowlands. The quest giver is Elder Helmar Blackford in Brookhollow. As a first step, you are asked to defeat 20 Exiles. He directs you to the ruins in the south, but it is far easier to complete this step by killing the 1 chevron Exiles in the rocks and woods in the north. (Note: you will only get credit for Exiles of a specific level, and there are two different levels of 1 chevron Exiles in the north, so you'll have to kill more than 20 to complete this step.)
After you finish this step, you have to report back to Elder Helmar. He will direct you to investigate Gerrin's Camp, near where you have just been killing the Exiles. You will need to Find Gerrin's Camp, read his notes (a book far inside the camp), and then kill 8 Exile Raiders. You can then report back to Elder Helmar for your reward, a level 20 weapon.
Rewards: