Be aware of direction of travel during sunup and sundown. If you are blinded, the cars behind you will also be blinded.
3:00 is early. I've done it a few times, but I often have troubles keeping the speed up in the dark in the wee hours of the morning (or late at night at the end of an epic ride).
Exercise can knock me out, so if I wanted to get to sleep early, perhaps a good ride just before bed.