We went to my folks who were 2.5hr away, when our girl was 8 weeks. She slept for the entire journey there and back. We were amazed. 2hrs is max travel time in the car seat. Take a sling, b&w cards, travel cot, sterilizer, spare clothes/lots of nappies /sleeping bag and sit in the back of someone else is driving. Good luck!
@Grace thank you!
@Jenna (Jen) very helpful, thank you so much!
I think the recommended time is every two hours!