Some books which are great for helping plan a family day out in Brisbane-
Most of these are out of print so you may need to keep an eye out in second hand stores for them.
Family Walks in Brisbane by Julia Thorn
Free and Low Cost Brisbane and the Coasts by Lee Mylne
Places for Little Faces Brisbane Susan Henderson and Gina Smareglia
Brisbanes Best Bush Bay and City Walks Dianne McLay
Also check out your local information centre or the Brisbane CBD Info centre in the Queen St Mall.