I've put this map past Jack and the response I got was "Yeah that looks pretty good to me!"
Starting point is at Homebush, then head down to the big McDonalds/Shell Service station intersection on the Hume Highway, then going in through Exeter, down Barrengary Mountain, through Kangaroo Valley. From there, there are two ways to get over to Berry, we can either drive straight over, or stop off at the Cambewarra Mountain look out for a few minutes to stretch the legs. From Berry, cut across to Gerroa (good beach to learn to surf at

) then up through Gerringong and Kiama, then all the way back to Homebush
Homebush to Berry via Hume Highway/Kangaroo Valley (first leg) is just under 3 hours
and Berry back to Homebush is around 2 hours, depending on Sydney traffic
(might have to zoom out a little

woops... )
https://maps.google.com.au/maps?saddr=H ... via=1&z=12