A "#trains and #trails" idea has been growing in my brain.
The idea is to catch a train to the end of a line, and #run from there to the end of a different line. In #melbourne with very rough routes:
Hurstbridge -> Lilydale (43km)
Lilydale -> Belgrave (36km)
Belgrave -> Pakenham (37km)
Pakenham -> Frankston (45km)
Hurstbridge -> Mernda (12km)
Mernda -> Upfield (27km)
... and so on.
In the same order as above:
https://www.strava.com/routes/3331553052377011402
https://www.strava.com/routes/3331553961634934494
https://www.strava.com/routes/3332944341991174900
https://www.strava.com/routes/3332948847360296692
https://www.strava.com/routes/3332946455506365330
https://www.strava.com/routes/3332947819171868562