This app was mentioned in 2 comments, with an average of 1.00 upvote
This app tells you all of the bike paths in your area as well as what kind of terrain it is (gravel, asphalt, dirt. etc) Then use google maps to really check it out, no need to purchase the maps, all you need to know is where they're at. Apple:https://itunes.apple.com/us/app/traillink-bike-trails-maps/id636875425?mt=8 Android: https://play.google.com/store/apps/details?id=org.railstotrails.traillink&hl=en