We just got back from the Cape, we drove from Brissy and the caught the train back from Cairns. There was five of us (wife & 3 kids) we got a three person sleeping berth and also had to pay for two sitting seats (but we never used them) - the cost was
$287.06 per adult in a sleeping berth
$132 per child
$399 for the car (if accompanied by an passenger)
and I think about $250 for the two sitting seats.
The train was great - loved it (it was actually a hilight of the trip) - I loved sitting in the dining carriage and having meals - it was great you could move around - clean toilets, excellent shower(s) - probably the only downside - the train did not have a tv (missed bathurst) nor internet (wtf it's 1012) and it was SLOW - 36 hours from Cairns to Brisbane - I know that it would take you that long to drive and spend a night somewhere but still at times it so slow i.e eight hours from cairns to Townsville.
The only other thing to consider is you need to be very careful with how you prepare your car - they don't like anything outside the cabin i.e. the roof rack cannot be loaded up with "stuff" and strapped down - they don't like anything in the back of the vehicle unless it's a fixture. No gas bottles, fuel cans etc.
We are experienced travellers and travelled light, so we had everything in plastic boxes (in the back) - 1 very large bolted in sealed box and then four smaller plastic "tubs" - at the end of the trip we packed everything down to a single tub which sat on the passenger seat - loaded up the plastic box with all the chairs and mattresses and then packed everything else into carry on hand luggage or very low in the car (QR driver must be able to move the seat back and see out each window) The only exception was the (oz)tent which was in the roof racks but they allowed this as it was the only thing and was strapped down well. In truth they may be more lenient but we did not want to get there and have them say "the cars not travelling like that".
Also they would not look at the car the day before to make sure it was ok to travel.
hope that helps.
de
