Most of the way across Pa is 2 lane with a narrow berm. Since the Allegheny Mtns run N -S, you'll be climbing and descending many mountain ridges. U.S. was an early highway, it goes through most every town it comes near, so you'll hit every light and business district. I use I-80 to cross the state, years ago I used the PA turnpike, but congestion and ever increasing tolls have changed my thoughts about that road.
I suggest you use Google Maps and drop the 'little man' onto various stretches of U.S. 6 to get a street view of the route.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI