Not an expert on Fla kayaking but I've run on all the beaches. Except for storm conditions, no Fla coastal water exceeds the normal range of roughness in the San Juans....due to action of wind from the three mtn ranges against tides.

My skills stemmed from canoeing and some small boat so in my second sea outing off Key West, the CG came out running a drill with 2-3 large rescue craft creating 2-3' clapotis around me. That was SJ normal.

If you access Google Earth on Flamingo, FL, you will see a tidal river running over the flats off the Flamingo campground. Running the tides here out to Shark PT or the Pelican Islands moderately equips skills for SJI.

Excellent beginners training, Florida Bay off Flamingo is shallow, warm, and boats are nearby. One step up, search for kayaking Savannah, GA. There's a school there. And Nantahala in North GA.

St George Island area is windy but very beautiful late summer as is Pensacola. Paddles across to Dog Island would near SJI conditions. Possibly off St Marks in Apalatchicola Bay.
Read Washburne, both books and Burch on navigation.

Running out of San Juan County Park is OK for developed beginners as there's a island side eddy to fall into. Out of Odlin is good for beginner's camping. You nare not out in the wilderness but conditions duplicate the experience.

I have a CD Solstice Titan with a Backup rolling cartridge and dry suit. My routine is go with the tide then turn into wave sets as tide carries me to point B. The technique, hahaha, is good for small craft warning conditions. Experts on the area zooooom around like waterbugs on a farm pond while I zigzag my way down the tide water.

The mapping is inexpensively done by entering overfalls and seamounts off free NOAA maps online into your waterproof and Sealine bagged GPS. As mentioned, this is a biggie. A calm pool as an 'overfall' like one north of Lime Kiln State Park, scene of a famous shipping accident turns into a full bore 2+ river rapid at low low tide with an opposing wind. And it ahppens as you paddle around the cliff corner. There's a hole right off SJCP south of Low Island. passed a small white wave crest there several times, I saw it again paddling down from Roche on my way into Smallpox Bay.

Having lost my good judgement after a successful day of not drowning, I headed over for a look. Damned if this small local wave unseeable from water or park didn't swallow us into a 6' hole then pop us back out.

If you go also try the Columbia at what is that park's name ?

and Long Island above Astoria.