Hey I know you're looking for a ride, but as someone who came to BronyCon back in 2014 and 2015 from State College I thought it should be pretty easy to get a bus via Fullington/Greyhound. Is there no availability?
-This operates on the assumption that you'd be leaving on the Thursday before the convention and leaving the Monday after.-
A quick run through on the Trailways website had 2 available time slots for departing from the bus stop next to the IST building on the PennState campus from either 9:30 am or 2:15 pm. Either way, it would be a 4 hour trip with 1 layover (presumably in Harrisburg) each way.