Re: visiting from California
You have made a good choice coming to Melbourne, it is a beautiful spot (especially when you get out of the city on the bay, etc).
There are many things you can do in Victoria and best of all, they can all have day trips taken to see them.
I would recommend taking a tour of the Great Ocean Road as there are a lot of caches down there and it is one of the most beautiful things in Australia.
You could also come down and explore the south east coast on the bay and see the famous Brighton Beach Boxes. There are a lot of caches around there all showing great spots.
I would also highly recommend seeing the Dandenongs (mountains) as it is just a brilliant area.
If you want to download the caches in these areas, I recommend making 3 separate Pocket Queries with the amount of caches set to 300 each (because these are big areas and you just do not know where you will be) with the radius being 100miles and coords being set to...
'Great Ocean Road' have them set to S 38° 51.160 E 143° 31.427
'South East on the bay' have them set to S 37° 54.340 E 145° 00.259
'Dandenongs' have them set to S 37° 49.863 E 145° 21.705
Good luck down here and have fun