Kay (USA) (2008/10/15): This book is by Lori Wick. It is Large Print. Love story set during WWII.
From the dust jacket:
As governesses on an Australian cattle farm, inseparable sisters Lorraine and Josie have lived far from their California home for four years. When their small plane crashes on a deserted island in the South Pacific, Lorri finds herself stranded...and the only survivor.
