Hi
Mission point at Bribie Island is only accessable by boat but a good spot for the kids and you can have a fire. The caravan at Donnybrook is where you can leave your car if you like and then its only a short run over to mission.
Its hard to find somewhere to have a fire these days--Rainbow beach at inskip point is another place that would be worth a look.
Just thought Bribie is not that far and well suited to kids.
Ronnie