Let's see. Bris Vegas to Maleny about 45 - 50 min, Maleny to Conondale about 15-20 min, Conondale to Cambroon about 10 -15 min. So that makes it between an hour and ten minutes to an hour and 25 min (give or take 5 min. I don't go that way. Astro_south would be able to tell you, he's been there a few times coming from brissy). Or you can go via Nambour then down the Obi Obi Road
out to Kenilworth and then to Cambroon in about an hour and 45 min.