Clarification on commute mileage for work and between work sites

I am a home infusion/hospice nurse that works for a major hospital chain. I commute directly from my home to a patient's home, work with them, and then commute to another patient's home, etc.  My work schedule is set so that I see the same patients on the same days during the month. Once in a while, I am asked to fill in for an absent colleague but otherwise my schedule is set. My supplies are mailed to me. Although we have a home office building several cities away, I never go there regularly; I don't have an office there at all. I use my car (and home to store the supplies that I am sent).  In fact, I have only been to the home office building  twice in the last year in order to get a respirator fitting and pick up an award for exemplary job performance.

 

I have been using a tracking app to track mileage, but I only turn it on when commuting between patients' homes, not while I am commuting from my home to their home or on the return trip.  I want to use these "in-between" miles for a job commute deduction. Can I do this?  Anything that I am missing?

 

Overall, I can put 100 miles on my car a day, and I work 7 days a week.

 

I also keep all of my receipts for gasoline, oil, car maintenance, car rental (while my car was being repaired), etc.

 

Note: I filed an extension to my taxes because I was unsure about how to handle these miles.