Forget about taking the overnight train trip (10/11 hours) from Sydney to approx AUD$92 (Countrylink) it is an expensive form of travel. Take the plane it should be cheaper, more comfortable and way faster. Hire a car and drive if you have the time for comfort freedom and great scenery. Please stay overnight in between the two cities to avoid sleep deprivation.

Campervans in Australia are expensive, for any comfort and privacy a couple would need a 5/6 berth which, including the cost of a powered site per day, will be in the region of AUD$325 .00 ...............hire a car and go B and B on the get as much freedom and it's way cheaper at around $75.00 for the car and $150.00 for the B and B.

Sydney airport - watch out for the transfer costs between the domestic terminals and the International.........thecosts are $5.00 per person for the bus and $4.70 for the train plus the luggage carts at $4.00 a throw.

Melbourne is a nightmare for a stranger to drive around, full of one way systems, you will need to be a claivoyant as the place is also not user friendly in the sign post department and impatient locals who know their way around give you no slack at all.

Try to stay out of peak hour traffic when everyone is racing to work.  Get a Melways Guide, it is well worth it if you plan to stay for any length of time.  If staying inner city, use trams and city loop trains.  There is a free tram that runs around the perimeter of the CBD.  Look out for hook turns but these only occur in the CBD.  Good luck!