Originally Posted by The Historian

Schuylkill River Trail, running from Monte Clare, Montgomery County, to Philadelphia - 26 miles.
Perkiomen Trail, running from Oaks to Green Lane - 20 miles. Connects to the Schuylkill River Trail at Oaks, giving you 46 miles of riding.

If you don't mind traveling a bit further, many parts of Chester County have low-traffic roads. East and West Vincent and East and West Pikeland Townships, for instance.

PM me if you'd like to meet for a ride.