Echoing what others have said, the longest, paved trial(s) I can think of is the Ohio to Erie:
https://www.ohiotoerietrail.org/
But it's not 100% paved, and it's not 100% trail. Biggest on-road gap is between the end of the Holmes County Trail in Frederiksburg and the Ohio and Erie Canal Trail near Massilon. Also, to me, that section is a bit hilly. Then when you get to the Canal Trail, it has lots of unpaved portions until you get into Cleveland proper. But it's also 300+ miles. You might get a 200 mile trip by going between Cincinnati and Frederiksburg, which would minimize the on-road sections and the unpaved sections, although I think you'll still see some of both between Columbus and Millersburg.