I went in as a chicken and managed to kill the final boss with around 2 minutes to spare, got a bunch of the chests in the last room.
What I found was I couldn't waste any time collecting chests in the first couple of rooms - instead, I just focussed on hitting the switches and barrelling through. Stampeding roar and Dash on cooldown is really important if you want to save a lot of time.
The other thing I did was switch from HotW to NV. I figured my damage was going to be very bursty, only needing to kill 2 mobs in the whole instance, so if I used my 3 minute CDs on both it should be really quick. Then again, I got through the thing so quickly my stuff had about 20 seconds left on my CDs by the time I pulled the War-God, so next time I'll save my CDs for him rather than the 1 trash pull at the second switch.
The biggest shortcut I think I took was once you get into the second last room, and you need to go to the stairs on the left to hit the switch, after you hit the switch just jump off the stairs and into the water, and run all the way across. This way you avoid the three lightning totems and the two hulk pats.
Overall, you should only kill two mobs: the mob at the second switch and the final boss. The first switch has no add, and the third switch has a pat that you can avoid by jumping over the fence into the water, then jumping over the fence at the bottom of the switch stairs while the pat is at the lightning totem. I didn't try stealthing, and that may work, but your speed is limited by quite a bit.
In the end I snagged 5 Burial Trove keys and something like 48 tattered page things. Hope this helped!
just stealthed thought the whole thing. think i killed 3 mobs next to the switch to the final door. could have avoided them too probably, was just being careless.
killed the last dude with a bit over a minute left and didn't really know where good chests were, so i ran around and collected whatever i could. there's a fancy one in the water in that final room i want to get to