Google Maps: set the destination as Thorney Heritage Museum.
Postcode: PE6 0QE
Latitude: 52.623
Longitude: -0.107
Bus: XL from either Peterborough or Wisbech/King's Lynn to Thorney Fish & Chip Shop — X1 timetable.
Train: The nearest station is Peterborough, then catch the XL bus from just outside the station to Thorney.