Currently sitting in brilliant sunshine in downtown Munich, we'll be back in July (suffer you lot).
Burra and surrounds is interesting, but I would spend something like a few days in the area and if there is to be a group meeting there, make our visit coincide with anything decided here. I would suggest August/September is the most friendly time, both for light and temperature, it can get quite cool there.
As for the Grampians, yep some interesting stuff and we always like to visit that area. With regard to food in Dunkeld, we prefer the cafe/restaurant opposite the hotel, excellent stuff and most of the locals go there as well, substantially cheaper to boot. Best time for the Grampians we have found, generally, is Spring, so late August to September is pretty good, although it can at times be a bit damp around then; better than bushfires though.
With regard to coffee on the move in the middle of nowhere, even instant coffee from Aldi is alright. Sort of like, "hunger is the best chef" kind of thing.
Mick.