Panama Canal - excursions in Colon

[ClevelandKid]

We are doing the Panama Canal cruise (FLL to Panama and back) next February.  On the day we reach Colon, two excursions interest me - doing the ferry ride through the Canal or seeing the Miraflores locks.  I thought the Miraflores locks would be a given, but I have read that there is no guarantee that any ships will pass through it while you are there, which would kind of defeat the purpose of going.  The ferry ride seems interesting but then our ship will be transiting the locks the next day (only halfway and then they turn around and come back).  Any insights, experiences or insights on the other excursions would be most welcome.