We have stayed at one called Hervey Bay Caravan Park, on Margaret st. Neat and clean, small, no jumping castles etc for kids. Easy walk to small shopping centre, or for a wander around the botanic gardens (check out the orchid house!). Right alongside the bowls club, but they didn't bother us. Short drive to pier etc (or longer walk).
Burrum Heads is not as far to drive as you might think, and is a nice relaxed beach style park by the river. Don't discard the idea out of hand.