Just FYI...
It would be nice to have a safety net of some sort for days where you just don't feel great. I have done it two ways:
1) I had a motorcycle at hand even tho I rarely used it to get to work. Public transport options would be helpful as well.
2) I got a job that was VERY understanding and able to live with me being late, leaving early, or just staying home due to weather now and then. I was late a few times and don't think I stayed home more than once or twice a year.
It sure took a lot of pressure off of me to have 1) and/or 2) in my back pocket. Pressure creates stress. Stress creates fatigue. Fatigue is not helpful to biking 20 miles a day, five days a week.
Cheers! And good luck however you do it.