The husband and I went to Jonathan Dickinson State Park on Hobe Sound, Florida, December 21-23, 2011. Due to a botched controlled burn, there were not many pine trees on the ancient dunes. Thus, Husband chose for us to camp near the river. The ancient dunes were pretty neat, but on a hot day one will definitely burn up. Take plenty of water when hiking. We managed to hike right before the sun set with daytime temperatures in the upper 70s, so we were pretty comfortable.
Nearby, on Jupiter Island, is the Blowing Rocks Preserve. It doesn’t compare to the California coast, but for Florida, it is quite impressive. Depending upon the tide and wind (an east wind is best), the water can spray up to 50 feet into the air. I never knew something like this existed in Florida.
I recommend stopping by the Hobe Sound Nature Center (http://hobesoundnaturecenter.com/) for more ancient dune hiking, a look at the intercoastal waterway, and a viewing of their animals (a chameleon! an owl! a hawk! baby gators!). The animals are well cared for, and the staff was very friendly.
Rumba Island Bar and Grill in Tequesta (http://www.rumbaislandgrill.com/) had yummy food. I had Rasta Pasta with grilled chicken. Unfortunately, it was a bit rich for my stomach for a camping and hiking trip (when I opt for blander food). But, boy!, was it delicious.