I did it. I ran on the treadmill every day of my trip. 13 days straight (one day twice). Towards the end, I had to cut back my miles each day to about 3 because I started to get a little pain in my knee. I was not looking for an injury.
Mostly the last few days were more physiological than physical for going on each day. Overall, I ran 54.2 miles in 13 days. That is about 4.1 -4.2 miles a day on average. This brings the total for the month to 64.2 miles over 17 days. When I get back, it will leave me 9 days left In the month. I should have no problem reaching 21 days and over 85 miles for the moth.