The good news is they have sewer. Most Florida State Parks only have water and power so more than 3 days gets tough without sewer. Hanna has sewer. They do have a playground area both in the campground and in the park. The park is very large and the campground is just part of it. I guess it depends on what you like. My wife and I like "rustic" camping and feeling like we are in the woods but enjoy having full power, water and sewer. If you want wifi, cable, swimming pools and planned activites, then this is not what you would want. If you like biking, camping in the woods, having campfires, etc. then you will like it.
We keep a log of each campground and put down the sites we like. I hope this is a good recommendation, but we like spots: 117, 256, 151 and 17.
Yes, we like Hanna park. Our son and his fiance' live in Jacksonville Beach so we like going there. It is definately kid friendly. There are lots of bike trails, but they are "off road" trails, so not smooth paved ones, but you can also ride out to the beach and walk your bike through the soft sand and then ride on the damp sand that is packed along the shore. So if you have bikes for the family definately bring the bikes. As far as being clean, it is your typical "rustic" county campground, so they are not "super clean" and there are no pools and planned activites like you might find in a motor home resort, but if you like camping in nature where you can have fires, you will like this..... to be continued...