The gold coast has good public transport down the beach, its around 30-45 minute though, but you can catch a bus easily enough. Taxi's are okay, and you can hire them with car seats ahead of time. We have done that a few times. If you are staying near the beach, the main road has buses which go everywhere. Its all good. I've often taken the train down to visit my friend & then hopped on a bus from Brissy... saves driving.