Depends on your personal lifestyle, if your are day person or nite person. I'm a nite person, so 4 days out of 7, I woke up at 2pm to start the day and end it at 5 am.
Have discovered early am hours is best for my fitness time, and late pm hours best for my work. So 3-days out of the week I balance it all by waking up 7am for the gym time, then back to sleep to wake up at 1/2p to start the day.
, you need to get out more often or broaden your network. I know many successful late-timer-entrepreneurs.