The best trout water on Penns is found from Coburn (confluence of Elk/Pine) downstream to Weikert. That's quite a fair bit of water. Access is fairly limited though.
You can access it at it's upper end at Coburn, as you know. A road parallels it for a while and dead-ends, but you can walk down from there.
Not far downstream, you can access it at Ingleby.
Downstream from there the next access is Poe Paddy. This is probably the most popular "middle" access point, and from here you can go up, down, or through the tunnel and cut off a mile or so of water. So this lot is often packed but you have to put it in perspective how much water it covers from the same access point.
Below there the next access is Cherry Run, and you can walk up from there.
Below Cherry Run, the road generally follows it to Weikert.
I'd normally tell you Poe Paddy is the best way to access that middle section. However, from your direction it's awfully convoluted to get to Poe (feel free to navigate miles and miles of dirt if you wish). That said, Cherry Run isn't a bad option for you, I like it better than the water at Coburn, honestly. Park and walk upstream. There's a whole lot of upstream!