Sorry your pup got sick ... my girl does, too. I need to take my dogs for car rides more often: the more they travel, the better they like it, the less they get sick.
Unfortunately, the gas prices have gotten so high I can't afford to just burn up a tank of gas so the dogs get to go for a ride
.
You did well: eat lightly, lots of water, frequent stops for potty breaks and a chance for the tummy to settle down a bit. It makes the trip longer ... but maybe more enjoyable if you can stop somewhere scenic that you would normally just drive past without stopping to see.
Sometimes, when human tummies get upset, crackers help to settle things. You can try bits with your dog, too.
Hope you get a chance to take another car trip soon: you live in a beautiful country with much to see.