Two weeks from today

This year, I've agreed to let Baleigh invite her friend Kaela to travel with us. We love her, she's like my second daughter.

My question is, what do I need to remember when traveling with someone else's child? Any tips, advice, warnings?

It's been such a smooth process so far that I feel like something is bound to go wrong at any moment! So any proactive advice would be greatly appreciated!