Hiking Italy

Look up the Via Francigena. I don't know much about it except that it exists, but it goes through Tuscany and sounds interesting. There is a website with details and some research would be in order since it might be a little too uncrowded. But I'd love to hear about it if you go!

Check out the Sentiero Francescano della Pace. It wanders through the hills and woods of Umbria, from Assisi to Gubbio. It follows the path supposedly taken by St. Francis of Assisi when he left his family and the comfortable life he was leading. It's about 40 km. We live near one of the places it crosses and uses local roads, and we see hikers all the time. We walked parts of it too. There are plenty of places to stay; the midpoint is a town called Valfabbrica.

For the Amalfi coast, there are two books that list all of the hikes on the coast and on the islands (one published by Sunflower and the other by Cicerone). I can't wait to go back and park myself somewhere near the tip of the peninsula and just hike. It's a great place to hike because in addition to stunning beauty, there are buses and ferries to get you around to trailheads, and you can pick one base.

I have not done the type of through-hiking you describe, but I have done some hiking on every trip to Italy. When I search locations, the first thing I do in zoom in with Google Maps and look for green areas, then I go to the website of each Italian park I find.
We love the sea, so we especially enjoyed Maremma/Ucellina park in southern Tuscany. South of the Amalfi coast, you might also research Cilento park. We only scratched the surface there, but it's on my return list also. Most recently we did a lot of hiking in le Marche--the options are endless!

Would love to hear more about it if you make it to Umbria, a big gap on my Italy experiences, but I'm sure there are books devoted to hiking there.

Thanks for the great suggestions. I also found myself on a rabbit trail last night about the Cinque Terre trails! All these ideas are great and I'll get researching!

No doubt Cinque Terre is stunning, easily accessible, and if you are a hiker then you can do the upper trails to avoid crowds, but if seeing few other people is a priority for you when in nature, then all of the other places mentioned are better choices. We found it easier to escape crowds on the Amalfi Coast since it is more spread out. You are on the right track!
Another thing to look into if you will be coming in October is truffle season--could be some nice festivals perhaps in Umbria.

Can second the Maremma regional park! It's not a pilgrimage walk, but is a beautiful hilly hike by the coast. Not busy at all because it's a little more difficult to get to by transit but beautiful. I did a day hike from Albarese but there is another town on the edge that has trailheads. Worth a couple days hiking and beaching if you can rent a car to get there.

Grazie!!!!