Took her out two times with a 75 war, 77 chanter, and 82 druid.
Both times she was in the camp where you get quest in the far west wall, then slightly north.
First time I engaged her with the war and then agro'd about 4 of her friends and pulled south. Keep in mind I had cleared the two guards at the camp exit and the patroller.
slightly out of camp, chanter locked down the four adds and then war and war merc got on Wald. Druid healed and ds'd main tank followed by ac and fire debuff then fire dot Wald.
Chanter slowed/crippled and locked down adds.
Tanks, well, they tanked.
Mask dropped.
Next encounter I decided to pacify the south part of the camp and then have the war arrow pull her to the west wall. We got one add due to her moving about, but he was locked down by chanter.
Repeated process above on debuff, dot, slow, etc... This was less mana intensive, but higher risk to agro a lot more than 4 mobs.
She dropped the mask twice, bummer as I wanted her melee.
Side Note: If there is a ph, I didn't have the chance to test out if the windcaller was one. She appeared out of nowhere both times, possibly someone else was killing the ph's? Nobody was around to pull her, so unsure on that assumption as well.

Light of the Forest
Ornate Windcaller's Mask