There are two major differences between pros and most of us: VO2max and recovery ability. These are both genetic talents. If you really knew how a pro trained, which you don't and which most of us don't because they don't tell, and tried to train like that you would burn out in a couple weeks. There are pros without tremendous talent in the former, but the latter talent is essential.
OTOH, it doesn't hurt to see what you've got. The worst is that you'll have to take a couple weeks off.
The program you quote is not off the wall. 500 miles/week or more for some pros. 75 hard in the morning, 75 moderate in the afternoon. Hey, give it a try.