Advice for driving with 1 year old?

Randi • In love with my best friend. ❤ 5/26/18 👰🤵 Mama to the perfect baby boy born 11/14/19👶💙

We're doing an 11 hour road trip with our son next weekend, he's 1 almost exactly lol. He sleeps alright in the car and is fairly patient when I'm sitting in the back playing with him and feeding him snacks. We will be taking a break every couple hours. I'm mostly worried because he loves to crawl around but it's November and we live in SE Idaho (travelling to Portland, OR) so...we can't exactly crawl around in the grass. We already have snow on the ground here lol. Does anyone have any advice?