I can relate with the anxieties of traveling overseas from what I've experience with this trip. In my past visits to Korea, I was solo and without kids so I didn't worry much about it. Plus when it was just me I didn't have to worry about language barriers, "culture shock", or food-intestinal incompatibilities.

Before the trip, I was very very stressed out with the planning. But everything turned out great! It's definitely an adventure but I think that's what makes it fun when you force yourself to move out of your comfort zones and experience new things. And believe me, I'm not a very adventurous person. DW is and she was at ease with everything during the trip! Anyway, now that I've got this trip under my belt, planning for a Hawaiian vacation (next year I think for my dad's 70th birthday) and maybe a European vacation (2-3 years from now) should be a cinch, right?
I laughed reading how you keep your youngest awake in the car because I used to do that ALL the time with our kids when they were younger. Because, if they fall asleep in the car, they without fail wake up when you try to move them out of the car at home. And when they wake up, they never go back to sleep in their bed for a real nap because they feel that 10 minutes of dozing in the car was enough. And when they don't take a nap, they get extremely volatile say around 5pm!

So, I would constantly sing songs, tell jokes, ask them questions while driving if I saw their eyelids getting heavy!