Just got back from Florida. Check out Everglades City and and Flamingo. Ivey House in Everglades City reasonable overnight rates ($70-$89) about 2 hours drive from Fort Lauderdale has kayak rentals - our tandem was new. We did a short tour on the Turner River. They have 5 day and 9 day routes. http://www.evergladesadventures.com/itinerary.htm. Many other rentals.

If you decide on the keys, John Pennekamp coral reef state park on Key Largo is a possibility. You'll have to rent kayaks elsewhere though as I think they are just a day operation. http://www.kayakfloridakeys.com/

Good luck and have fun. If you're there in April, maybe we'll pass you.