How to GPX! Creating gpx routes and installing on iPhone. GPX studio. OsmAnd Maps app. 

If you just want to know how to get GPX onto a phone then jump to 11:30
useful links-
GPX studio - (to create new gpx files)
gpx.studio/
Cornwall byways - (to find new legal byways)
map.cornwall.g...
OsmAnd Maps App- (to show gpx route on your phone)
osmand.net