Loren Pope wrote the CTCL book, he died over a decade ago. I don’t think the CTCL schools or administrative organization receive profits from book sales (and it hasn’t been updated since 2013).
The 45 or so schools are not confined to the NE https://ctcl.org/college-map/
It really just seems like a loose association, kind of like the public LAC association. The schools are known for offering solid educations, attracting a diverse set of students, providing good financial aid (and many stack FA).
Agree that all colleges can change lives.