When entering the park, go right at the intersection toward Pendleton Lake. Park in the paved lot. Now, look at the lake. Over on the left there is a dam that holds the lake water back. Walk over that way and you should find a trail along that end of the lake. Follow over the dam and you will find the creek at the spillway. How you get in there is up to you. I've been in and out of the upper end from both sides. It's dangerous enough up here.
Lower down is a lot worse. You be the judge, but there are 5 decent sized falls here and they all look nice. The way to the lower falls is by accessing the very steep trail that emanates from the Pendleton overlook area. From the parking lot, head out over the grassy area toward the overlook and look to your right. Head into the woods over in that corner and look for a trail. There's a sign there warning you not to, but that's the way down. It's very steep and dangerous.