It depends on the baby, I think. Be prepared for lots of stops! Luckily, babies love the car so she'll probably sleep most of the way. Just make sure you bring lots and lots of nappies and a changing matt, a bunch of blankets, hats and mittens etc (though the need for these things depends on if your car has air condition and good heating I suppose). Bring some baby panadol too, just in case. If her teeth have started decending, bring something for that too. We use bonjella on Aurelia, it says for 4+ months but my GP said it was okay to use on her at 3 months. I suspect that there are other similar products out there for younger babies.