Travel north towards rising sun's beam, having deviated from course (4,6)
I believe the answer is:
gone astray
'travel' is the definition.
I know nothing about this answer so I can't judge whether this works.
'north towards rising sun's beam having deviated from course' is the wordplay.
I cannot really understand how this works, but
'north' could be 'n' ('N' can be a synonym of 'north') and 'n' is found within the answer.
'beam' could be 'ray' ('ray' can be a synonym of 'beam') and 'ray' is present in the answer.
'course' could be 'east' (I've seen this before) and 'east' is found within the answer.
The remaining letters 'go' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?