From Stevenage train to King's Cross St. Pancras Underground Station, Tube to London Euston, then train to Watford Junction. 50 min £20. From Stevenage, Bus Station line 301 bus to St Albans, St Peter's Street then bus to Watford, Clarendon Road. 2 h 12 min £5. From Stevenage taxi to Watford. 26 min £102. From Stevenage drive to Watford. 26 min £4.