1. Since you've never been, be ready for a fairly long travel on dirt roads in there. Not such a big deal but always surprises first timers. No, you didn't make a wrong turn (well, you may have, but even if you didn't, it feels like you did as you just keep going).
2. You can fish from your site. Penns runs right by it. But many will opt to drive up the road a mile or so and park at the end. From there, the road upstream (straight) is gated and you can go up that way towards Ingleby. Or the tunnel path also comes off just down from the dead end, and angles downstream, quickly crosses a walking bridge, and then goes into a tunnel. Through the tunnel then puts you 2-3 miles DOWNSTREAM of where you just were, and 1-2 miles down from the campground! You can go up or down after passing through the tunnel too. Downstream is the ALO section.
3. Zero cell signal in there. If your lucky, you can get enough coverage to get texts just on the other side of the tunnel. That's about the best spot in the valley I've found. Otherwise, you gotta jump in the car and go up over the hill again, which is a bit of a hike.
4. Cherry Run is park at the end of the road, go through tunnel, and go left (downstream), walk 2-3 miles to get to Cherry Run. There is an access at Cherry Run. But it's nearly an hour by car, as the roads go WAAAYYYY around. It's quicker to walk.
5. Through that tunnel, a nice, crushed rock walking road parallels the stream (same road as the bridge and tunnel itself). If you have the setup, a bike greatly eases getting around in there.
6. Remember to carry a flashlight! On sunnier days, the bulk of the action happens right at dusk and just after dark. Expect to come out by flashlight.