I believe there is some kind of the paper/website in PA similar to MD Equiery. At least I remember seeing one at the PA Expo. Meanwhile I'd look for recommendation at COTH. They have bunch of local people from MD, VA, and PA. Last year when I couldn't ride I found my exercise rider (eventing trainer living close by who travels, and who also now gives lessons to my neighbor) by recommendation from there.
"Life isn't about waiting for the storm to pass: it's about learning to dance in the rain..."
"When we are no longer able to change a situation - we are challenged to change ourselves."
"How people treat you is their karma; how you react is yours."