House-on-wheels is def. fun for kids and some adults too, like me..haha
The 4-berth is definitely the choice for you, more car-like. With shower rcmded if traveling in summer. But I'm not too sure it's available in Brisbane, book early.
Andy is right. The only place that forbids campers are underground car parks in the city centres, due to height constraints. May even be able țo park overnight in the themeparks' carpark too, for early entry. (winter, off-peak season). I'll choose to do away with campsite parking hereforth. Beach/ gardens/playgrounds carparks have generous lots and public toilets. Nothing beats a swing/obstacle course for kids upon waking up/after breakfast.
Groupon your theme parks tickets. I still have 2 golf-puting course tickets for kids to giveaway, if you're keen.
Do make a 2 days trip to Springbrook NP, 1 hour from gold coast, for a 2 hrs waterfalls walk in the woods. Call Ben direct +61488236236, for <$100/night (off-peak) luxury accdm at gold coast. (hilltop condo or beachfront shared house, featured above)