We went on a car trip when DD was 12 months old. we drove 11 hours in 1 day, and were travelling with BIL and their 11 month old.

We tried to pull up for a rest and something to eat every few hours (probably why it took 11 hours) and mainly to let the girls run around for a bit. We had a 20 litre esky in the car with drinks for the girls, so we could give them a bottle when they wanted something to drink.

Last year we went to Byron Bay, so we split the drive into 2 days. DD was 6 then.
We splurged and got a portable DVD player for the car and we didn't hear a single thing from DD either day, except when we said maybe it was time to have a rest from watching the screen.

We took plenty of little snack foods and I made some little snacks up in zip lock bags for DD to have in the car with her.

If you are having milk cartons or juice etc that you want to store in a fridge, ask the place you are staying what size their fridges are. I know it sounds silly, but we got caught out a couple of times with little fridges that we couldn't even fit a 1 litre bottle in! (DD had just discovered Sippah straws last year just before we went away)

For us (Mum & Dad) we got a Navman just for the trip away, and what a life saver it was (once we learnt how to use it) No arguments trying to follow maps etc... But we're country folk, so city driving/freeway/entry's exits etc, is something new (and scary) for us LOL!

When we left Byron, we went to the Gold Coast for a few nights and stayed at a place called Treasure Island. We stayed in the self contained cabins. They had putt putt, a pool with a mini slide for the kids, spa for the big kids, tennis, and a games room that DH, DD, BIL and I went and spent a couple of hours playing games! At the end of the block was a Subway and across the road was Harbour town, full of discount shops and a woolies as well.
There was also a bottle shop near the subway from memory, so very nice to go and get a bottle of red and just relax the night away with.

Nic