Cars, Buses, Trains, and Hoofing it. What's Best?
When you're making your way through the valleys of the Lunigiana, a car zinging carefully along the narrow roads is likely the best way to get around. I'd advise a narrow car, as well as tapping the horn in several short bursts when approaching a blind corner.
Big buses are using those roads as well as you and the other two people who are on the road. When they honk, stop as close to the verge as you can and prepare to back up if you need to.
You can get between the big towns on the railroad, which makes many fewer stops than it did just a few years ago. The four main stations are Aulla-Lunigiana, Villafranca-Bagnone, Filattiera and Pontremoli. Other places, Like Fivizzano and Gassano, are served by bus.
There are many small roads it's safe to walk on in the Lunigiana. A strada bianca is a white road, named for the color of gravel, and you can generally walk easily, darting off to the side to avoid farm vehicles and the like. You might meet people working in the fields. Engage them if you can. It's all part of the experience.
The officially marked Via Francigena is an ancient pilgrimage route that's been re-jiggled to get pilgrims off the fast, narrow roads. It runs from Pontremoli to Filetto, then to Aulla and on to Sarzana in Liguria. For a map of the route in Italy and discussion about pilgrimage, see the Via Francigena Map & Guide. Taking stolls along parts of the route will bring you into contact with modern pilgrims who carry the traditional scallop shell as well as big backpacks.
Go check out my guide for the best free things to do as well as itineraries and travel tips to make your trip unforgettable.