Live on Marco Island. By all means, check out Shark Valley and Anhinga Trail. Latter is closer to Miami and Homestead. There is a boat tour in Everglades City at the park center there. Also, Ding Darling on Sanibel Island (which you mentioned), Estero Lagoon off Ft. Myers Beach (behind the Holiday Inn), Corkscrew Swamp Sanctuary off Immokalee Rd. in Naples, Turner Road Canal off U.S. 41going towards Miami, the Faxahatchee Boardwalk also off US 41 before you reach Turner Road if you're coming from Naples/Marco, and Eagle Lakes Park in Naples. There aren't many places to stay in Everglades City. You're better off staying on Marco or in Naples. Homestead has some nice places, but I think you'll be able to see more in SW Florida. It's also less crowded as you're away from Miami.
Right now the weather is starting to get a little cooler here, which is great as it was very hot and humid here this summer. Have heard the kayak trip in Ding Darling is very nice, but haven't tried it. Just too old at this point. This is a pretty good time of year to visit as the snowbirds haven't all returned yet. It really gets crowded after Christmas.
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