I kinda followed the instructions posted by Ngaguti. I ran (using sprint when it was available) all the way to the Brandy Buck Bridge but, I did not jump in the river there. I crossed the bridge and skirted the river staying on the bank. This allowed me to cover more ground at a much faster pace than swimming. There were a times when I had to swim to avoid creatures along the river bank.
I made it to the Ent at the North Western side of the lake and had 38 minutes to spare. I was never aggroed.
If you've done the Breeland one, you know very well chickens can swim, of course. And knowing they can, this one is no longer one that can't be done without an escort. It becomes one you can do with your eyes shut.
Just head east through the Shire to the Brandywine Bridge. In the middle, jump into the river and swim north. Stay to the center of the river and swim all the way to the middle of Lake Evendim. Turn NNW and swim to the Evespires, talk to the Ent and you're done.
I used the Fowl Fleetness skill regularly to boost my swim speed and got to the Evespires with over 15 minutes to spare. It's possible if you don't use the speed boost you could be cutting it close on time--not sure. But the closest I got to danger was a wolf standing near the road in the Shire. An easy trip.
This one may be rougher than the Trollshaws one. You have to run the chicken to the named ent at the Evespires (sp?) located at the far north west corner of the lake.
I'm not even sure that chickens can swim...
Just like the Trollshaws one, I don't think this could be done without an escort.