In reply to Spready:
If you're interested using all the sources you can find online to plan a route, can I suggest one more?
Down here in and around the Peak, where it's relatively busy and I'm often looking to get off the beaten path (but still on some kind of a path), besides the OSM I often find it's worth having a look at the Strava Heatmap to see where people actually have been going.
Sometimes across open ground, if there's been enough traffic to create a defined path, you can actually see the 'fuzzy' bits where the path disappears and everyone follows a different route until they pick it up again.
Slightly annoyingly you do need to be logged in to see a useful amount of detail though - but a free account works fine and there's no need to pay a subscription.