All the advice you've got so far is good especially the eating one, this applies to all trips really, (and if you do need to buy food, stop at the small local cafes, much better value than the roadhouses). You don't say how old Bub is but if old enough (and you can afford it) the small portable DVD players are going for about $130 these days. Works wonders.

Stop at play grounds and insteed of eating fast food or simular, we go to supermarkets/delis and buy meat and rolls, bottle of juice and anything else we need and cook a bbq, lots of free bbq around the place, this may take an hour but it is worth it, kids get to run around and mum and dadcook a good lunch. Also we ofteren stop at op shops or $2 shops and give the kids $10, they'll come out with a lot of *junk* but it keeps them happy. Things that make noise are always a winner with littleys to. See how you go, you may even want to break the trip up in two days. I done over 1300 km in a day once, 23 hours, I'll never do it again, I only had one child then, she was 3, we drove to pick up hubbys 1st daughter and had to get back the next day, boy was that hard.Good luck and im sorry to hear about your relly.

hi how are ya,
from the time i was 11 til i was 15, every single school holidays, i had to take a trip with my little sister to south australia to see our dad, we either took the bus or dad would come and pick us up.. he also had a little girl ( my half sister) and they would plan to leave at night, which she would sleep most of the way,  they planned stops to change her nappy/diaper and give her a feed  towards the end of the trip, which was 7.5 hours each way.
hope this helps
xx channy

I did similar when mine was 6 months old.  Make sure you leave a lot of time for stops.  We took a lot longer and stayed the night in a cheap motel for the night.  Every time we passed through a town I would stop for a meal or coffee and would give her something to eat or a feed and let her have a play for a while. It was a really pleasant trip, just because I was able to keep with her regular meal times and she could have a bath at the regular time.  By that time she was having 3 main meals and 2 snacks a day as well as breastfeeds so keeping those meal times regular I think is what made it so pleasant.  I was told to have someone sit with her in the back to play with her too that way we wouldn't have to make so many stops, we would only have to stop long enough for a meal, I could get a coffee on the go instead of stopping for one, but I'm a single mum and had no one else to sit in the back of the car. But that might be an option.