I flew across the bass straight in a p28r Arrow and it was tops. Was VFR and the weather at the time was fortunately OK. I have heard that the weather can change quite rapidly.
The route i would recommend is From YSBK to YSCB then YMAY through Latrobe Valley and island hop to flinders island. I is a flight that will give you a great deal of satisfaction once completed
Good luck with it and enjoy