Apron Falls is located on Duncan Creek, which has several waterfalls along it. Rather than plunge over a cliff or tumble down a series of cascades, Apron Falls slides down a massive rock slab, making it almost look like fun to shoot down it in an inner tube.
Look at your map and note that there are TWO forks of Duncan Creek. The east and west fork converge right at the posted trailhead coordinates. Apron Falls is on the EAST fork but to get to the cache without trespassing you must cross the WEST fork first. Look for the primitive log bridge over the west fork about 250' upstream from the posted trailhead. Once across the bridge the trail goes up the west side of the east fork and for most of its length it runs high above the creek along the edge of the canyon wall. The trail is rudimentary and good route finding skills will be required. So keep your nose to the ground and follow the faint boot/animal tracks. An occasional piece of colored flagging tape will let you know you're on course.