Travel east in fast car, one seen at Goodwood, perhaps (8)
I believe the answer is:
racegoer
'one seen at goodwood perhaps' is the definition.
(someone at the Goodwood Festival of Speed)
'travel east in fast car' is the wordplay.
'travel' becomes 'go' (synonyms).
'east' becomes 'E' (synonyms).
'in' is an insertion indicator.
'fast car' becomes 'racer' (race car).
'go'+'e'='goe'
'goe' inserted inside 'racer' is 'RACEGOER'.
(Other definitions for racegoer that I've seen before include "Eg, one attending Derby" , "Regular attender at, eg, Aintree or Epsom" , "One on course" , "Frequenter of 51 [ASCOT]" , "for speculative investments?" .)