The nearest airport is Pisa International Airport "Galileo Galilei" only 30/40 min far by motorway, connected with scheduled flights to all major European cities. Not far there's also the Florence Airport "Amerigo Vespucci".
The closer Railway Station is Cecina (LI) 10/15 min far by car or Taxi.
Check the Trenitalia website for train timetables.
From the North: take the A12 Highway Genova-Rosignano and continue on Variante Aurelia motorway till Cecina Centro exit. From there follow indications to Montescudaio.
From the South: exit Cecina Centro from Variante Aurelia motorway and follow indications to Montescudaio.