You'd be fairly unlikely to get an internship in Victoria as an interstate graduate because you're in the bottom category for priority matching. You absolutely wouldn't get a job with the big tertiary hospitals (eg Royal Melbourne has stated they haven't employed any interstate graduate for several years now) due to the way the system has worked out. The smaller, more rural hospitals will probably end up hiring a few interstate graduates but there's no guarantee. You're free to apply back to Victoria and see how things turn out though, since you're not obligated to take an offer you receive.
As for after your internship, it's still difficult. I would move interstate on the assumption that I wouldn't be coming back to Victoria for at least several years after graduating and treat anything sooner as a pleasant surprise.
e, Having said all that, you are obviously very likely to get an internship in the state you graduate from and most people build a fairly happy life over 5 years of living somewhere.