I've read some not-so-good things about the Cowboy Trail. Poorly maintained in parts. Lots of goat heads in places.
This is paved, but only 74 miles and in ID:
https://parksandrecreation.idaho.gov...coeur-d-alenes
Paul Bunyan in MN is paved for 120 miles:
https://www.paulbunyantrail.com/
There is also at least one paved connecting trail. The Heartland Trail of 47 miles.