Continue downstream to the little pond with the small waterfall spilling into it. At the base of this waterfall, you'll find another GPS cache (2/5), circled in the screenshot above.
After picking up the cache in the water, go back up the hill and cross the stream to the wooden ledge built into the rocks.
Climb on top to find another GPS cache (3/5) and some arrows.
Move to the other edge of the wooden ledge and hop down onto the smaller ledge below. Now look to the right to spot another Ghost Hunter totem (4/10) hanging in the trees.
Shoot it for the challenge.