I loved Tulpehocken Creek in Lebanon/Berks county when I was living there. A good portion of the stream is known to have natural reproduction of brown trout, but you'll also find some stockers, obviously. Also lots of carp, if that interests you at all. PM me for specifics if you're interested.
I never really did much bass fishing when I lived in the Lancaster/Lebanon area. There are farm ponds around with largemouth, I'm sure, but most of the smallmouth waters I fished weren't spectacular. The Conestoga river in Lancaster is supposed to have bass, but I never did manage to catch one.
Definitely not a high quality bass river like the Juniata river here near Lewistown - my first cast in the river after I moved up here I caught a heavy 14-16" smallmouth! I'll never forget that first cast. Someone on the forum put me on to that spot, actually. Not that it matters much with the Juniata - it seems to be infested with smallmouth.