My son Richard, who is just now obtaining his master's degree in library science from the University of Oklahoma, works for the public library in Tulsa. He also is an intern for the library at Tulsa Community College, and recently found himself putting "science fiction" stickers on the spine of Illuminatus!, among other books:
So students at TCC can read it.
The bad news, though, is that the Tulsa Public Library, which serves a pretty good-sized city, does not have any Robert Anton Wilson books. Patrons of the library, however, do have access to quite a few RAW books through the consortiums that the library belongs to.
I just now checked by running a couple of searches, and the Cuyahoga County Public Library, which has multiple branches and serves much of the Cleveland metropolitan area, does not have any Robert Anton Wilson books. (You can do an additional search to go beyond the library system and borrow RAW books from other libraries.) The Cuyahoga County system also has no Robert Shea.
CLEVNET, a network of dozens of northern Ohio libraries including the Cleveland Public Library, does have many of Robert Anton Wilson's books. Also a couple of Robert Shea, but several are missing, including All Things Are Lights.
Which raises a couple of points: Many libraries allow their patrons to suggest new titles. If you are chummy with your local library, you could ask it to buy the new edition of Cosmic Trigger. Also, if you have a library with RAW titles, check them out! Books that sit on the shelves ignored for years get weeded out of the collection.