The reading of that College Calculus Book for the incoming freshman

Here is the guide from a Johns Hopkins University math professor on how to attain the ability to read a college level math textbook. His big tip is:  READ as in practice.

Unlike high school the pace is really rapid in university level math courses.  In a high school Calculus AB class or BC class, a student may spend 200 hours in class to cover a College semester's worth of material. At the university the time is about 50 hours to cover a semester's material.

In many k-12 programs reading a math textbook in grades 6 through 12 is de-emphasized for the book may be non-existent.