I start early but about the time that I usually wake up, 3:30 or 4:00. Working WITH my natural rhythms seems to make sense to me. If you don't usually wake up early then trying to start then would be a struggle right at the start.
I have done several 1000-mile days that were not planned as SS1000 rides, it just happens that I have a destination 1024 or 1050 miles away.
I do these trips with zero tolls -- 2-lane roads are far more interesting to me than freeways. That choice makes mine take a bit longer, 21 or 22 hours.