I stayed at Pialba last june july with my 3 kids and had a great time. Any of the beachfront parks are good to stay in, the facilities are old but very clean. You will find that the majority of the people in the park are either retired couples staying there for the winter or back packers there for a night or two. Make sure you take bikes for the kids they can ride in the caravan park but there are heaps of bike tracks. The Urangan pier at the southern end is great for fishing on the change of tide.