milk and traveling question. Please Answer?

Hey mommies! Im going on our first trip today with our one month old daughter, when chloe was born i couldnt get her to latch on so i gave up on that and started pumping exclusively so the trip we're going on today is 4 hours long. My question is i have about 20oz of milk in the fridge, could i freeze that and take it on the trip and just let it sit and thaw for 4 hours since we dont have a cooler or anything? and how long will the refrigrated milk survive once taken out of the fridge?