Langkawi via train

[ahtal68]

Planning to take the Senandung Langkawi from KL Sentral to Arau, then onwards to Kuala Kedah or Kuala Perlis which ever is nearer to Langkawi. Anyone know how far Arau is from the Kuala Kedah or Kuala Perlis ferry terminal and whichever takes the lesser amount of time to get to Langkawi and back to catch the return train a few days later?
Appreciate your help. Thanks