station strolls
The nice thing about trains (and coaches) compared to planes is that you can hop off wherever you fancy without needing a parachute.
Here are some ideas of where you can go for a stroll with particular emphasis on France and Spain
France
France
For France, I've made my suggested strolls as a set of downloadable PDFs along with interactive Google maps that you can use to go for a wander.
Spain
Spain