From Heathrow Central Bus Station line 230 bus to Brook Furlong, Milton Keynes Coachway (Milton Keynes Coachway Car Park), bus to Central Milton Keynes, Food Centre (Central Milton Keynes Food Centre B4), then bus to North Gate Bus Station. 2hrs 19min £17. From Heathrow Terminals 1-2-3 Underground Station Tube to London St. Pancras, train to Bedford Railway Station, then line 41 bus to North Gate Bus Station. 3hrs 26min £28. From Heathrow Central Bus Station bus to High Wycombe, Bus Station (Shopping Centre), line 300 bus to Aylesbury, Bus Station (Bus Stn Bay 6), bus to Central Milton Keynes, Abbey House (Central Milton Keynes Abbey National W4), then bus to Northampton, Drapery. 4hrs 59min £20. From London Heathrow drive to Northampton. 1hrs 10min £14.