[jvm_]

Another resource for finding footpaths/routes is

https://www.strava.com/heatmap

They've aggregated tons of bike and running routes so you can see where other people have ran/biked before. Good to use in the woods when the trails aren't very obvious, just use the 'find me' button on the map and then you can see where you are and which trail goes where.

[IanCal]

This is fantastic thanks. I've moved to a new area, and some of what's here looks like it might be people in cars (some is definitely on trains) but I can see some good routes over fields. Particularly this shows me that a lot of people go down a route I thought connected but wasn't sure and couldn't find the time to check (a long way back if it's not part of a loop).