@nataliefranke I know this may not help, because the problem is so big. But from another formula mom to another, I'm happy to also look when I'm out if you want to share what kind.
@kateshellnutt We just did this with our 18 month old. Two days and 18 hours. Lots of stops, utilized rest areas where she could get out and run and get a snack. We tried to make stops fun so she looked forward to them! Seemed to work well! Good luck!!