Forest of the fallen tier 4 quest

[asmodeal]

The quest involves not using any mechanical traps which happen to be the only trap available for some of the paths.
I thought I could handle it with Olympus pillars only but on wave 3 I am being completely overwhelmed.
I don't really see which combination of mystical pillars I have to use so that I can protect the path without towers and let my towers deal with the other side of the map.
Does anyone have a good strategy or does it require a very tweaked character just for this quest. I feel this going to be the second quest I drop after the one where you are suppose to use trap only.

[strigvir]

The right part can be defended by placing geyser with phys vulnerability and olympus. The top part depends on your tower spec, put whatever you want there. The left you have to deal by yourself.

[pecoes]

I do not think it's possible to lock down one lane completely. When I did this quest I ended up standing next to the Olympus Pillar at the defense points and killing everything left and right.

EDIT:

I used 2 Phoenix Pillars and 4 Olympus Pillars in the north and a Frost Pillar in the east.

[asmodeal]

Geyser and Phoenix are two traps I never use. BTW geyser is mechanical so that would not work for the quest, doing the map is a piece of cake if not for the quest requirement.
The right side is pertty fail proof with one olympus pillar and the two special traps so that is not too much of an issue. I did not think of using phoenix on the top part to delay waves, I guess the knockback effect is the best delaying effect available on mystic pillars only.
Not sure if I can just guard the two gates by myself, I might try again at higher level.

Thanks for the answers.

[pecoes]

Yeah, Phoenix is mostly about the knockback. It's not as good as Olympus otherwise - slightly less damage and significantly smaller range.