Coming from the Autostrada del Sole (A1), you take the exit at Orvieto if you're coming from the north, and at Attigliano from the south. You then follow the signs for Civitella d'Agliano. Il Poderetto is after the hamlet of San Michele in Teverina, on the Strada di Santa Maria. 
Coming from Viterbo, you take the Strada Teverina for Bagnoregio. Before you get there, you turn right for Vetriolo. A few kilometers after Vetriolo, but before getting to San Michele in Teverina, you turn left down the Strada di Santa Maria at the foot of the castle of the same name. Following a untarred road for about a kilometer, you reach Il Poderetto.