As a group, anglers are a lazy bunch. They (meaning those anglers other than you) choose the path of least resistance, opting to drop a line in water closest to the road, closest to the trail, near the campground and nearest the parking lot. Even more industrious anglers don't walk far enough away from public access points, giving up to the lure of the water after only ten minutes of walking. This gives you your first few identifiers for a secret trout hotspot.