Take the Via Appia Nuova in the direction of Albano, past the turnoff for Ciampino, to Santa Maria delle Mole (with traffic lights) and then the following the road to Nettuno (with traffic lights), starting at the slope for Frattocchie. At the first major set of traffic lights, turn left in the direction of Castelgandolfo, driving down the main street till the village.

Once in sight of the papal palace, continue along the main street up to the traffic lights.
Here turn left passing immediately under a bridge that connects the papal palace to its annexes.
Take the street that overlooks the lake, go right down towards the left until you reach a junction which you cross going straight on and at the crossroads for VIA ROCCA DI PAPA you pass a bar – restaurant called “Le fratte ignoranti / Fantini” , continue along the main road past the restaurant “Miralago”, up to a final junction where you turn right towards ROME.

Go down the road following the signs for Ariccia along the end wall of the Chigi Park.
Turn right at the ARICCIA square.
At this point you can opt for two solutions. 
Either you go immediately to the left going down to the town of Ariccia to a large car park under the bridge, from which you can take an elevator that comes out in front of Palazzo Chigi and walk to the Villino directly after the bridge.
Otherwise, continue driving across the bridge and, immediately after, turn right into Via Vito Volterra, and just after the first corner on the left, at no. 1, is the Villino Volterra.