My experience is that they start opening up at 4:30 am
Check-in, according to CO, must be done 45 minutes before the flight.
The lounge does not open until 5:30 am so I can never use it when leaving this early.
I would get there at 4:30
There is an elite access security line but that is shared with wheelchairs, families and airport employees.
Last time I flew early out of SFO, it took me double the time to go through the Elite security line as it would have taken me to go through the regular line; All wheelchairs and employees cut in line at the front.