There is a bus that goes along this route pretty closely. The Monbus route leaves from Sarria weekdays in the afternoons and stops along most of the major stage towns on the Camino.
Compra online billetes de bus y consulta horarios. Si lo prefieres alquila un vehículo para tu viaje en grupo. Viaja seguro, confortable y barato con Monbus.
I have attached a pdf of the schedule so you can see the times at each location. There may be a different schedule on weekends, but you can look that up or check on the website.