PA is a HUUUUGE state. You may have better luck looking for individual cities, like Pittsburgh or Philly, or whatever's inbetween.
I'm from da Burgh myself and I know there's a ton of cosplayers here and in like, a three-hour-driving radius, but that seems to be the other side of the state from you! I also know a handful of people who cosplay in Philly, so they're out there!
One of your best bets may also be to try your local (or the most local) anime con's websites. Even during the off season people like to gather, and you may luck out there. If you have any local colleges, try their anime clubs as well--you may find cosplayers there, or people who know where they're hiding. A lot of my friends aren't on internet forums very often, so don't be afraid to network via word of mouth.
Overall, good luck, and sorry I'm all the way on the other side of the state!