It's been quite a few years but we've stayed at Blue Spring State Park
several times when I lived in Daytona Beach. I used to take my two sons canoeing in the St. Johns River from there. The spring´s year round 73 degree water can be enjoyed by swimmers, snorkelers, and scuba divers but it'll feel freezing cold with the air temps in the 90's.
I don't know if any changes have been made there in the last several years but I recall the sites as being secluded each in its own alcove of scrub oaks. Nice private setting for each site.
Hook ups were adequate for the times, can't recall if they had 50 amps or not; I didn't need it at that time.
Unless you have expectations of a resort type setting, I think you'll thoroughly enjoy your stay at that park.