It is possible it could be held in Melbourne, but it is not likely, in my opinion. Most likely , it will be held in Ballarat. For these reasons..
It is the community where the crime took place, it is where he comes from, and it is where his victim comes from. It is a Ballarat community matter , and, the accused is entitled to a jury of his peers, from his neighborhood, so to speak. Her family are entitled to a court near home, to lessen travel stress. His family, also, is entitled to the same consideration.
Ballarat is on the circuit of the Supreme Court, it is a regional city, it's not a little town, Supreme court cases have been held there before, it's not a new thing to Ballarat. In fact, Ballarat has a magnificent court house, from memory. I hope it has not been pulled down and some concrete ghastliness put up.
The problem lies in jury selection. However, juries are properly instructed and any difficulties winnowed out. And the selection pool would encompass the entire Shire of Ballarat, quite a large area. There would not be many of his peers available for jury duty, not many 22 yr old men put themselves down for jury duty, not many are ratepayers, at that age, so it would not be exactly 'of his peers'..
Any juror on that trial would already know they are up for jury duty this year, or early next year. Everyone is sent a letter, first to tell you that you are on the list, then to ask you if you can do it, or do you have commitments that make it difficult. This is sent way way early, so no one is wondering for long about jury duty.
I would think he would not be transported up the Ballarat and back to Melbourne every day. It would be done by video, but maybe that might be the way it goes, .. I would be surprised by that, though.