Depending on where near Brisbane you are going it should be close to the roar & the stags will be starting to move around a bit.The roar generally starts with the first major change in the weather around Easter .Hopefully there will be a nice early frost or temperature drop around this time & you will be able to hear the stags roaring up on the ridges & in the gullies. It's a nice time of year. I will be away camping with the family at Easter but I would love to be out there as well. What suburb in Brisbane does your sister live in?