Hobart - take the MONA ferry. Parking is limited and the ferry is fun. My favorite dining in Hobart was at Glass House. The eggplant was so good we ordered a second serving (they are small plates). And that was something I never thought I would say - eggplant so good I want seconds.
Melbourne - Crown Towers is awesome and yes, it has a casino, but I have been there twice and still don't know where the entrance to the casino is at. It isn't like Las Vegas where the gaming is right in front of you. Park Hyatt is fine. Langham is about to undergo a reno and I can't remember when without checking my notes to see if it will be in Dec.
Food in MEL - Chin Chin, Seamstress, Izakaya Den, Cup of Truth coffee and so many more. You can't go wrong.