Interesting that you would mention this! My family and I were reminiscing just a few days ago about the two wonderful vacations we had - many, many years ago - in wonderful Bonaire! I did a google search on Bonaire and came up with some interesting diving and hotel websites for the island, with great photos. I don't think much has changed since we were there, primarily becuase it is so out of the way. Regarding your question about cruiseships, I don't think there are any that visit there. Ships do stop at Aruba, I believe it is very popular, and probably at Curacao. On another website posting a bunch of us were commenting on how few iteneraries there are with the Southern Carribean. Most of us are sick of the touristy Cozumel, Cayman, and Ochos Rios - (of course, I remember Cozumel before it became just bars and vendors ..... again, many years ago. Now, however.......sigh..) I think you are going to have to to to Miami, and fly across the water to the Dutch Antilles - probably is a 5-6 hourflight. BUT - if you are looking for the best snorkling in the entire world, quiet, and interesting land and plant features and bird life, Bonaire can't be beat! I believe you will have to fly in to Aruba or Curacao, so you might as well spend a day or two there as well...
You bring back fond memories of thousands of flamingos, HEAT (lets not forget that, but it goes with the territory), and - again - the best snorkling ever.
Hope you get there!