From my experience, in Kentucky, spring salamanders are almost impossible to find from late may to early October, and can only be found during the cooler months. However, I'm sure they are active longer in Pennsylvania, since it is much cooler there. In Kentucky, they can be found at night during rains by road cruising, or by simply walking around springs with a flashlight, as well as by flipping rocks and logs during the day time. When searching for spring salamanders, look out for larvae as well as adults - the more larvae you see, the more likely you are to find adults.
Hope this helps - I'm not sure how different their behavior is in Pennsylvania than in Kentucky.
-Ananth.