My general rule (which I don't obey) stock up on greens!. Ye ol' spinach and kale have wonderous nutritional values I'm told :p
Pizza wise VIC would have many more options as opposed to SA I'm sure so finding a fat food place that does vegan cheeses on pizzas shouldn't be a problemo.
In the mighty (or not) SA, there are a lot more places coming out with vegan cheese options

, such as: Godzilla Pizza in Brighton, Lightsview Pizza in Northgate, Pick 'em Pizza in Fullarton and I thiiink 360 Gradi Pizza in Magill have Vegan cheese options (I'm guessing they do as they have a vegan option for their 'Margherita' pizza.
I'm sure there are many more in ADL, that's just a few I can think of .... Admittedly I can only eat pizza cooked / made by my mummie as nothing else compares ... nope not ever! :p