Pittsburgh area twisty riders tend to hang out at either:
Not much traffic here these days.
The good roads (sweepers and twisties) are in WV and southeast OH. There are some decent roads in western PA (Laurel Highlands and mtns in central PA), but the good stuff is out of state. Luckily, you can get there in an hour.
North Fayette is near Oakdale and McDonald, right? If so, this loop is pretty twisty:
50 west to jct 844
R on 844 west into WV to jct WV 88
L on 88 south. Follow to Peters Run Rd (BP on left).
L on Peters Run. Follow to end at jct 40
R on 40. Follow into Elm Grove. Get back on 88 south.
Follow 88 south to end at jct 250
L on 250 south. Follow to Hundred/jct 7
R on 7 west to New Martinsville. Follow to (almost) end at jct 20.
NOTE: you may want to head into New Martinsville for gas at this point
L on 20 south. Follow to jct 19.
L on 19 north. Follow to jct 218.
L on 218 north. Follow to end in Waynesburg, PA
Get on 21 west in Waynesburg, follow to jct 18.
Bear R on 18 north. Follow to jct 231
L on 231 north. Follow thru Claysville to end at jct 50 (just outside Avella).
R on 50 east. Follow back home.
NOTE: 231 is more of a country road than a highway. There is an unmarked left-then-right jog in the section north of Claysville. You'll be at a T/stop sign just past a bridge wondering where to go. Go left, then quick right to stay on 231.
That's a good day of riding (~280 miles). Note that you can cut from Hundred to Waynesburg, via 7 east to Blackville/218 for a shorter day. Or you can take 69 north from Hundred (turns into 18 in PA) to head back toward Washington.
FINALLY: BE CAREFUL OUT THERE. More than a few riders total their bikes in the WV twisties. The guardrails are unforgiving. The "25 MPH Turn" signs should be respected. Lots of blind turns, decreasing radius turns, unmarked sharp turns, gravel, deer and other hazards down there. Don't say you weren't warned.