You will arrive from the Deep Roads at Aeducan Thaig and will have to take a right into a carved tunnel off the main road. There are lots of deepstalkers and you will run into a few bands of darkspawn. As you travel through the carved tunnel you will come to a fork in the road. The path to the bag of limbs is to your left, to your right a dead end as well as in front of you. There are a few items to pick up (none of any real consequence) as you continue left you will come into a great room and will run into some deepstalkers and darkspawn. Eliminate everyone and the bag of limbs is tucked in to the left of a poorly built barricade on the other side of the great room. On your map it would be furthest north and west you can go.