my daughter rarely sleeps on road trips. shes 3 1/2 we've been doing trips since she was 6 months. i strongly suggest a portable DVD player. if not toys r us sells a car seat tray that hooks to the seat. perfect for playing w/cars, coloring and eating off of. take a ball w/u to pull out at rest stops. i keep a small suitcase w/toys in it next to the car seat so she can reach them herself. we also go to the dollar store and get a few new toys and books for when she starts to get cranky and wanting out, give her the new toy/book and shes occupied again for an hour sometimes more.
we sing silly songs, play "what noise does it make?" which is a "game" she made up where she asks what noise an animal makes i tell her something way off and we spend about 3 mins on each animal until i'm right. shes getting a little older so we've started to teach her i spy. and we name colors we see on the road.
at 10:22 PM on Jun. 4, 2009