we did a farm stay down at phillip island when the twins were 3 years old and it was awesome. it was in winter as well. the farm owners were great and let the kids collect and use the eggs for breaky, and showed them around the farm. we had our own cottage as well so it was great for a family. whilst down there we did the penguins etc a really good quick get away.
we have also done a weekend down queenscliff- not much around but a nice place and we did one down at warnabool as well
have a look on take a break to see what is around for a last minute deal
definately recommend a farmstay if you get the chance!!!