Great Boondocking
So we spent the entire Memorial Day Weekend at this city park and it was wonderful. They've been redoing everything there trying to recover from the past hurricanes' damage and it's going great. Okay it's boon docking, no water or electric but the sea breezes keep the heat and humidity to a bearable level and in our Pop-Up (PUP) with the windows unzipped it was actually cool at night.
Lots of sand, sun and very few trees but plenty of security and the lifeguards are there sun up to sundown. My youngest and I watched the sun go from deep red to bright yellow as it rose over the white sand dunes just steps from our campsite. You can also camp on along the channel if you prefer though we like the access to the lagoon much more pleasurable with 2 young daughters.
If you need a point of reference what the beaches on the Atlantic side look like watch the movie "G.I.Jane" since the beach scenes were filmed there directly across from NAS Mayport. It was cool to watch the large cargo and car-carrying ships make their way down the channel heading for Blount Island and Jacksonville to unload or head back out to sea.
One last thing, realize when the sea breeze doesn't blow the "no-see-ums" are really bad but bug spray or burning sage on the fire keeps them away.