That's great you had nice weather ...it can vary so much in November / Dec , same for Adelaide ,This year SA has had a very dry month of Oct with above average Temps ,Sydney always gets more rain than SA and quite often in bucket loads.
We came home from our GC trip via Sydney in 2013 we delayed our trip not leaving for the GC till Oct, we flew to Sydney, First week in Nov, we traveled by train from Syd to SA the weather was warm in Sydney ..but pleasant we had a whole day in Sydney to explore its a Beautifull city ...So is Adelaide .. You might have to consider including our visit to our state on a visit one day it also has lots to offer .. Many tourists visit Kangaroo island on a visit here