I love this feature in Google Maps, you click “Avoid Highways” and see what comes up.
These alternates add about time to your trip, but they add character, too.
They used to call these the Blue Highways. William Least Heat-Moon wrote a book about them. He had coined the term to refer to small, forgotten, out-of-the-way roads connecting rural America (which were drawn in blue on the old style Rand McNally road atlas).