Favorite tips/tricks for road-trips with a toddler???

We will be headed on a road trip this coming weekend and would like all your tips and tricks for driving long distances with an 18 month old. She’s always been excellent on long flights but has never done a road trip or any amount of time in a car for more than 5 hours. We will be stopping every few hours to let her stretch her legs and already have lots of snacks.