From Heathrow Terminals 1-2-3 Underground Station Tube to London Kings Cross then train to Kings Lynn. 2hrs 58min £30. From Heathrow Central Bus Station line 727 bus to Trumpington, The Busway Trumpington Park-and-Ride (Car Park), bus to Cambridge, then train to Kings Lynn. 3hrs 37min £31. From London Heathrow drive to Kings Lynn. 2hrs 10min £24.