a day sack, a credit card, a map, and some time
All it takes really is a step and a word from someone about the direction. A pack on the back is optional, really. Wearing pants with many pockets will help assuage the anxiety.
I would like to walk the Chemin de St Jacques de Compostelle again some day and do it without a day sack. It is possible, I think, to walk it with nothing on the back.
When I walked the Way during the fall of 2013, I wore a small sack that I had bought from Rick Steves many years ago. Thirty plus days of walking from Puy-en-Velay to St. Jean Pied de Port, approximately 750km, called for minimal support if one stayed in gîtes, hotels, or chambre d’hôtes, I thought.
Coleridge, Wordsworth, Muir walked many many miles without the need of backpacks.
Each day of the journey, I saw fellow pèlerins who carried backpacking packs even though they did not sleep in tents but sought roofs for the night, gîtes for the most part.
What did I carry in my sack on my back, Mack?
Two water bottles, one extra shirt, one extra pants, two pairs of underwear, top and bottom of long john underwear (used instead of a sleeping sack in some gîtes), four pairs of socks (two pairs of liners and two main pairs), one large light pancho, one light umbrella, iPhone, camera, fork-knife-spoon.
What did I not carry?
Hiking poles, tent, sleeping bag, cook kit, cooking stove.
un Voyageur 
Thanks for sharing this Michael…it looks like a terrific hike!