When I was a kid (one of three) we took LOTS of family road trips. We even took two months to drive across the country one summer in a Volkswagon camper van (suffice it to say it was not a luxurious journey). When on these trips we kids were typically bored out of our minds. Both of my parents smoked (ugh). Reading in the car caused motion sickness (double-ugh). So we played games or sang songs, and did a lot of asking “are we there yet?” – yeah, it was pretty awful.
[Ours was like this, but white instead of green. And there was a tent that attached to the side when we parked each night.]