I aint no poet but maybe try;

have put off all suitors gay, all lords and men of might,
And spend my days upon the shore, his homeward ship to sight

But I am not at liberty to walk with any man
Until my true-love John returns from his ship's command.


Just drop the 'long'

Might even try;

Until my true-love John is freed from his captain's command.


Whatever it is a good song with a nice twist in the tail. Would love to hear it being sung.