Lots of options, not all are good...
First question: does cost matter to you? The more highly thought of publics in the region tend to be $$$ - Mystic Rock (Pete Dye southeast of the Burgh), Olde Stonewall (highly rated, not recommended by yours truly) north of the Burgh. Both are pretty pricey, imho not worth the cost.
Next question: walkable to a flatlander? Man, that eliminates just about every course in the Burgh except maybe Fox Chapel...
Even Oakmont is pretty hilly (best use of hills in all of golf, no question, anyone who says otherwise is certifiably insane, even if his name is Tom...). North Park, my home course and where my heart lies, is pretty hilly. They don't call it the North Hills (our geographic region) for nothing. Birdsfoot is pretty hilly, as is Quicksilver. I've walked both, would say Quicksilver is probably an easier walk, but neither is what one would call easy, at least from a hilly standpoint. Green to tee walks on both are pretty manageable, but the elevation changes are significant - not mountain courses, but signficant.
Proximity to the Turnpike? You might want to check out some of the courses north of the city, as Butler and Cranberry are both close to Turnpike exits. Cranberry Highlands is probably convenient to the Turnpike. Haven't played it, as it was built right around when my son was born and I stopped playing much golf.
My gut recommendations: I really like Quicksilver. They used to host a Senior Tour event (back when it was called the Senior Tour...). And it's not very pricey, though I haven't been there in awhile. I love North Park, the muni I have played by far the most, but I would hesitate to recommend it to anyone who isn't an old school walking purist. Conditions are iffy (it's a muni), hazards aren't much - but it is a wonderful walk, imho. If you choose it, please send me a message, I would love to join you if I can (heck, I'd pay your $15 green fee...
).
Public golf in the Burgh can't really compare to private golf. We're talking basic basic mom and pop type stuff versus all world privates, unless you are spending an arm and leg for the highly overrated MR and OS.
Wish I could comment more on Bedford Springs, it's rebirth coincides with my relative lapse from the game... It's not really western PA, imho, but I can see how others might call it that. I think it's relatively close to the Turnpike, from what I understand.
Pittsburgh National - formerly Deer Run - is a solid modern course that's relatively cheap. Kind of a b@tch to find, although GPS makes it much easier. I always enjoy a round there.
Lastly, a shout out to Pheasant Ridge... a friend of mine is involved there, so I am HUGELY biased, and the former owner, deceased, was the subject of some wonderful threads on here. If you go there, please contact me, I would love to join you there as well, or at least buy you a beer.
(P.S. didn't mean to make it sound like I was inviting myself, though in retrospect I think I kinda did... just excited to see someone ask about my home. I love it for reasons that go far beyond golf.)