I am arriving in MEL Airport and I'm thinking of going to SYD by train, because through the Internet seems quite reasonable, with beds and so... So I will not be using my AN ticket and I'll cancel my hotel ...

Please advise on whether this idea seems wise.

I am arriving in Mel in the early hours of the morning and planning to get the same-day night train to SYD so that I get there at 6:30, the following day.

I would like to have opinions from Aussies informing if
1) is it acceptable ?
2) can I get out of the airport and leave baggage at the station (which station, by the way - I know Melbourne city)
3) Are the trains comfortable and can one sleep ?
4) Is it something a tourist usually enjoys ?

Any other advice you think suitable.
Thank you in advance.