we cruised down the east coast from NC last yeaR with our 2 boys , then 9and 10. Cumberland island was a nice spot that we enjoyed , but that was really about it . To be fair we were trying to get a move on because it was cold ( nov) We did not find anywhere in FL that was friendly to cruisers let alone families in fact there was a guy at a marina in FT pierce that was down right ignorant to us, and FT L the boating capital of the world was no better.
The Bahamas however was Fantastic , friendly and safe . Great swimming snorkeling Warderick wells park was very educational and has insperied our boys to look at the planet as a whole and gave them a first hand experience with conservation and preservation. I imagine the FL keys would be a very similar sort of experience and we may try that this year though our draft is a bit too deep. The oportunity to visit new areas was not wasted on our boys . They actually like to go to museums now! When the oportunities arise take educational tours , nature walks etc. it costs a little more but it is learning without school and who does'nt like that? Also make sure you have a way for them to get off the boat without you having to drive them , it provides a sense of responsibility and independance, as well it makes the mommy and daddy time better if you get my drift. Have a plan for discipline. There will be no you are grounded and stay in your room on a boat. One friend of ours , and we now use this as well would make their kids write an essay. You know "why I shoild not talk during the morning wx broadcast "stuff like that. We use pushups 100 if you leave the light in the head on. The point is not punishment but an oportunity to be busy while you think about what you should have done plus if the're angry when they start them they usually are'nt when their done. The worst part? Homeschooling. By Far.
Oh I almost forgot cruising with kids is great and those that have not done it have missed a really fun experience. Kids engage other kids as well as adults and oportunities appear that may not have without kids . Like the time two turtle tagging biologists saw our kids and invited them to go turtle tagging . One of our boys actually caught a 40 lb turtle by himself....priceless.