Anyone else traveling for Christmas with LOs? Let's commiserate and share tips.

We're leaving tomorrow with our almost 16 month old. Our travel agenda for tomorrow:
- Leave our house at 7am eastern
- drive to airport (45 minutes)
- 2 flights (2 hour flight, then a 3 hour flight) with a 2 hour layover in between
- After landing at 5pm central (6pm eastern), a 3 HOUR DRIVE to the in-laws (they live in the sticks!)

AND on the way to their house, we have to stop at Walmart to pick up Christmas gifts and baby stuff like diapers for the week. I anticipate we won't get to their house until 9 or 10pm, so probably a 15 hour travel day. I am dreading tomorrow SO MUCH... and now that I've written it out, I'm thinking I am crazy for agreeing to this travel. LO has flown before but nothing like this.

Would love to hear your tips and tricks!