There’s legal access to it via the SGL/SF roads in the public lands to the north, but you have to climb down (and back up) the ridge to the north to stay on public land on the way in/out.
I suppose you could also climb the AT out of Port Clinton and descend down to the stream off the south ridge too. Largely the same issues as the northern approach, plus the additional initial climb on foot.
There isn’t any (legal) access as you note via the mouth at the end of the valley in Port Clinton.
I’ve never fished it, but know several guys who have. They all report similarly...a lot of work to get to, and a lot of rhododendron once you do get to it. It has Brookies, but that combination has dissuaded me from fishing it, the latter especially. It’d make for a fun day exploring for the adventurous angler though. I’d recommend snake gaiters for the hike down the ridge if done during the warmer months.