Our cats were taken everywhere in the car for 1 month and then they were good to go. No carrier, just a harness and red leash. They initially meowed and had to be trained to stay out of the drivers area.
But then for the rest of their lives they were OK and just slept while traveling. One cat went for 2 airplane round trips to FL in a carrier under the seat. Not a problem, but she was well seasoned with cars, RVs and boats. For long travel a simple litter box would be appropriate.
I wouldn't want to use a carrier for anything other than a airplane.