As promised, here is additional information about revisions to the path after Pieve Santo Stefano (Stage 8, p. 95).
Keep the first line of the paragraph that reads, “The road turns to gravel then comes alongside the wall of the Auto Strada Statale 3bis.” Replace the rest of the paragraph with this:
Turn right at the first archway under the highway and follow the driveway left, past the house and through the metal gate (please close it behind you). Keep on this road, veering left at the next two Y intersections while going uphill at a moderate rate. Stay on the road as it leads through a logged area and then goes steeply uphill. About 500m later the road becomes a one track path and reaches a summit with views to the reservoir beyond. About 200m later the path joins a road from the right which you follow as it leads steeply downhill. Watch your footing carefully as the road plunges down on sandstone bedrock and small, loose gravel.
I strongly advise against walking on the original route behind the Euro Hotel. The path has eroded off the hillside and is precarious for all walkers.
mille grazie. we are starting from La Verna the 21st!