Have another go for the best ever journey, ultimately (5)
I believe the answer is:
retry
'have another go' is the definition.
(I've seen this before)
'for the best ever journey ultimately' is the wordplay.
'ultimately' says to take the final letters.
The final letters of 'for the best ever journey' are 'RETRY'.
(Other definitions for retry that I've seen before include "take second opinion on case" , "Hear (a case) again" , "Advice following failure, initially" , "Have another go" , "Put on trial again" .)