You decide which city to start your journey, because it is not really essential to follow the whole route. You can start at your home and reach the closest stop to you by public transport. Many cities along the Via Francigena are also important railway junctions and with the road network you can reach any destination. The only inportant thing is not to hurry. See the sections below, dedicated to all public transport serving the route, which allows you to shorten challenging stages of the journey or alternating between walking and other modes of transport.