Traveling tomorrow, any tips on how to make it as comfortable as possible?

Tomorrow I'm taking a trip with my daughter and it's going to be an 8 hour drive. I've made this trip with her before, but she was under 5 months, so she wasn't quite as mobile as she is at 12 months. Are there any things you guys have found to help during a long car ride with your older baby?...I know we'll be making frequent stops, but I'm worried that she'll have a meltdown being stuck in the carseat for so long. Any tips on what could help?