You're thinking about it wrong. It's not that she doesn't do well on long car rides, it's that you haven't tried things to make the ride easier. If you have to make a long drive, kep her up longer tha usual, and leave at night after bedtime. Sucks you have to drive while everybody sleeps, but it makes it easier.
Rotating you and mom in the back with her also works if it has to be during the day. Wake her up early, and pushing out nap time is another trick.
Don't stop living because you have a kid. You may have to change the way you would normally do things, but it can be done. If I could make the drive back and forth from CO to CA with a 2yr old, and a 6yr old, anybody can do it.