Drive at night, portable DVD player, snacks, & toys! Made a 15 hour drive with 2 little ones over the summer. Just keep them occupied when they're awake but hopefully they will sleep most of the time!

Driving at night is a good idea!
But if that's not possible just make sure to take breaks every few hours & get him out the car seat to stretch. He'll probably sleep majority of the time.

Drive at night! We made a 20 hour drive with a 7 month old and we drove at night. She slept the whole way and was also teething. But she was so good!