A chuck survival bag JIC she gets carsick. Towel, wipes, bottle of water, container to hold under her chin, spare plastic bag or 3! Keep it close at hand too in her footwell not in the boot
Speaking from experience???

i just said to DH that we need to remember stuff in case she gets sick - she is fine going from here to the other side of Melbourne, and never really whinged going up and down the mountain at home, but some of the roads are much more windy between here and canberra seeing we're going the "scenic" (aka 3 hour shorter) way lol