Glad my comments might have been helpful. Sin e I don't really know what you're cycling, travel or outdoor proficiency is, it's a little tough to make suggestions. Not sure how much time you said you had.
Here is a website from one of your compatriots from the land down under:
http://www.cycletrailsaustralia.com/
It seems like there are parts of Autralia that are not awful during summer. However, having said that...
I cycled in Central America last winter. I didn't make it to Nicaragua but I've heard it's amazing!
It really depends on time frame, type of cycling, mileage and all that. Are you camping, credit card touring? What type of bikes, strictly road, some off road etc. If you have a FB account there are several chcle touring forums. People from all over tbe world are posting. Just click around, you'll find them.
Keep us posted.
R