I have fished Penns in both Poe Paddy State Park and Ingleby. The Poe Paddy C&R section is pretty neat as you take an old railroad grade through a tunnel to get to the C&R section. Ingleby is nice because it is a little harder to find and I've experienced less people in this section. I talked to a local up there that told me during green drake season that it is "bring your own rock". Good fishing and good evening hatches/spinner fall at both locations.
Another neat little stream I fished in 2005 was Clark Creek just north of Harrisburg. It had a C&R section that had old "K" dams that made for good fishing.
I've fished Spring Creek in Fly Fishers Paradise a couple of times. It is very technical but good midge fishing.
I fished the Delaware in lower NY and was not impressed. There were blankets of sulfurs on the water and I didn't see a single rise...but apparently (from above) I missed the good water of the Catskills.
Bottom line, you can't go wrong with Penns!