My longest single day non-stop drive was around 18 hours.... Never even left the province. The flight alternative required me chartering my own plane and would have cost many many thousands of dollars more, so I went with driving as it was the cheapest option.
As a European, these distances are mind-boggling. If I drive 18 hours, I can drive through half a dozen countries (or more, if you optimize for that) and easily get from the Baltic sea to the Mediterranean sea.