I like to spend the night in Cracker Barrel lots. You should ask the manager for permission and where to park. They often take on supplies around 4 AM and don't want you to block the delivery trucks.
Since you will be meandering along the coast you will likely be traveling on Route 98 along the coast in the Florida panhandle.
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If you have a car you might take a look at Tate's Hell. It's kind of interesting although not extremely so. I'm not sure you can get an RV in there but you probably can since you have a class "C". There's a boardwalk that goes out over a dwarf cypress forest.
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The Ochlockonee River State Park campground has received some good reviews however I've never stayed there. The park has some pure white squirrels you might see and the rare red cockaded wood pecker is there too.
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It's a little off route 98 on the Sopchoppy highway. However if you continue on the Sopchoppy highway it comes back in to route 98.
In the town of Panacea there is the Gulf Specimen Marine Laboratory. I found it very fascinating. Panacea is on route 98. Check a map.
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A little farther on you come to St. Marks National Wildlife Refuge. There's an interesting lighthouse there.
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I haven't spent much time on the East coast of Florida. However I did photograph the Lowry Park Zoo in Tampa.
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I also photographed the excellent South Florida museum.
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After you get to Fort Myers, assuming you are interested in wildlife, you should go drive around the loop road a few times at Dinner island Ranch Wildlife Management Area. It's not far from Immokalee.
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Just about every animal in Florida has been spotted there at one time or another including panthers and bears.
The surrounding area can also be productive for wildlife spotting.
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You might also take a look at Corkscrew Swamp Sanctuary. It's closer to Ft. Myers than Dinner Island is.
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Of course if you're not interested in museums or wildlife then you can disregard this post. BTW, it would be a good idea to check on the hunting season prior to going to the Dinner Island Ranch and surrounding area. There could be some hunters in there. They scare a lot of the wildlife with their shooting.
There are shore areas west of Ft. Myers such as Ding Darling that might also interest you. I found this place extremely interesting years ago before I started taking photos:
Fort Myers, Florida | Museum, Botanical Gardens, Research Laboratory | Tours, Events - Edison & Ford Winter Estates - (239) 334-7419
I hope some of this helps you along the way.