If you get bicycle directions, it might take you through Neville Island, down 51 to McKees Rocks Bridge (take the sidewalk there) and then up to California Ave in Brighton Heights. It has been years since I’ve ridden that, although I recall a nice shoulder on Neville Island. I never rode it in rush hour though. 51 from Neville Island to McKees Rocks bridge might be intimidating. Once in Brighton Heights, it’s a lot easier riding. Take California Avenue to the North Side, or drop down to the trail which will take you to the north shore.
Maybe someone knows a better way to get to Ben Avon from Sewickley that doesn’t include 65.
It’s totally doable, but the amount of traffic you’ll see will depend on how much climbing you want to do.
If you want to come in north of the Ohio river, the route is as follows:
Beaver St to Glen Mitchell.
Go up Glen Mitchell. Nice climb, with low traffic.
Get on Blackburn, go up a little more and then down to I-79, where it becomes Mt Nebo Rd
Go up Mt. Nebo until you reach Roosevelt Rd. This is perhaps the least appealing part, but Nebo now has a bit of a shoulder so you’ll get some room while going uphill. It’s also a relatively short climb.
Take Roosevelt all the way into Emsworth. Super nice road with very low traffic.
Go through Emsworth, Ben Avo, Avalon and Bellevue on Center Ave/Church Ave/California Ave/Lincoln Ave (it’s the same road). Low speed traffic, as those who want to go fast are on 65.
Once in Brighton Heights, go on Benton Ave and then down McClure Ave, which takes you to Woods Run. From there you can reach the North Shore Trail
On the southern side, the route will be much flatter but will also see more traffic, especially trucks.
Cross the Sewickley bridge and get on the shoulder on 51 until you get to Coraopolis
Go through Coraopolis and then cross into Neville Island. After you cross under I-79, you’ll encounter the Neville Island bike lane. It’s a glorified shoulder, so watch out for debris.
Cross into Stowe township at the other end, and ride on Island Ave/51 until you get to Chartiers Ave in McKees Rocks. Follow it until you get to West Carson
On West Carson, I usually ride on the road until I get to the Corliss tunnel, then get on the sidewalk and follow it all the way into the city. It’s a meh ride, but it’s about as flat as you can make this trip.