hey dude, i grew up in mansfield at the base of mt buller. abour 3.5 hours from melb to the top of the hill. Through winter its kinda hard to stop and take photos in the snow with a good view in the background. There are car parks on the way up that you could stop in but once at the top (as high as you can drive) they will park you in a massive carpark with all the other snow bunnys which will make it hard to get decent photos.
Police require all 2wd cars carry snowchains (4wd at own descression), its illegal not to. Even though most of us wouldnt fit chains under car its still compulsory. Another thing to keep in mind is melting snow (on a sunny day) runs through dirt and onto road ie car is generally pretty dirty by time you get up there.
Entry through the gate during winter is about $28 i think, free in summer.
In summer on the other hand you have MASSIVE empty carparks with a view behind, incredable photo oppertunity but of coarse there is no snow, safe place to have a bit of fun too considering there is noone else around.
hope this helps out all interested!
brett