Right? Most of those are all the kinds of regular maintenance things you button up BEFORE a long trip. Windshield cracks are usually either quick fixes or fixes that can be delayed or patched until you finish the trip.
Frequent enough stops to limits butt pain and blood clots isn't such a bad idea though.
You are already capable of communicating to your cat that you are in pain. Be honest. Make sounds of pain when they hurt you, the same way you would train a kitten not to bite or claw with malice. Your cat will understand. Just don't get angry. It's easy for cats to forget about empathy in the face of anger.