Course travelled, by the sound of it? (4)
I believe the answer is:
road
'course' is the definition.
(I've seen this before)
'travelled by the sound of it?' is the wordplay.
'travelled' becomes 'rode' (eg travelled on a horse).
'by the sound of it?' shows a homophone (sound like).
'rode' is a homophone of 'ROAD'.
(Other definitions for road that I've seen before include "Abbey -, Beatles album" , "See 2" , "Way travelled by boat" , "'The . . . . to hell is paved with good intentions'" , "See 10" .)