I've got good news about that part of your post I've emphasized above. It is possible to spend more than 90 days at once in the Schengen Zone as a tourist by using bilateral treaties. Australians and New Zealanders seem to be especially fortunate this way. Check out the webpage linked to below and then search the forum, a lot has been written on this here.
Contact embassies or consulates in Australia and you may find that you can walk continuously from Rome to Lourdes to Santiago to Fatima by spending up to 90 days each in Italy, France, Spain and Portugal without having to leave the Schengen zone. The problem may be more a matter of money than time but you would save yourselves return Europe/Australia tickets.
It involves work, record keeping and care as, once your "free" 90 days are up your route and method of travel has to keep you out of countries you did not get permission to stay for an extra period.
I spent nine out the last 12 months in Europe. 90 days in the Schengen area. Then 95 days out of the Schengen, in Belarus. Then 90 days in the Schengen. Words cannot describe how much I love Europe…
thefreedominitiative.wordpress.com
The URL of the above is
https://thefreedominitiative.wordpress.com/2015/04/24/unlimited-visa-in-europe-for-free-maybe/