A few km south of San Quirino turn left here:
Coming from the left in this foto, do a quick right and then a left to cross Via Napoleon Aprilis:
Soon the dirt road runs into Via Portolana, which takes you through Villa d'Arco. When you reach Via Villa d'Arco, go straight across and onto another dirt road:
Don't go left here. Take a right and the road then makes an immediate left:
Soon you're back at the junction with SP65 and can head on in to town.