I agree that the best fishing in Lebanon County is not for Trout, but for Smallmouth and other WW fish species in Swatara Creek. Pretty much anywhere in Lebanon Co. on the Swatara will produce fish, just try to avoid any stretches that appear to be wide, very shallow riffles. If you’re looking for Trout, the Quittapahilla and its larger tribs are stocked pretty heavily, but they tend to not fish that well in my experience outside of the first few weeks after a stocking.
There’s wild Trout once you get to the ridges to the N/NW. There's some AMD issues up there, but most smaller, mountain streams will give up a Brookie or two.