High magick practicioners can be called ceremonialists or high magicians/mages.
High magick is very ritualistic and very hard to keep hidden unless you have a sacred space that will be undisturbed.
I would suggest that while you remain in the broom closet that you focus more on low magick aka folk magick which is much more easy to conceal.
I use it quite a lot right in public and no one is ever the wiser. If you need to chant something, I like to put a bluetooth or earpiece in my ear. They see me talking and believe I'm on the phone. They may think I'm a little strange, but I don't really care.
As for books, many bookstores have places to sit and read. They usually have a far better assortment of books than libraries and for all levels and if you buy a hot chocolate from their cafe, you can sit there and relax for a long time undisturbed. Just be nice to the books and put them back when you're done! I only buy books that I want to keep for reference, but many I just read (take notes) and put them back in the spot I found them. I'm a huge bookworm (I'm sure you can tell from my posts) and I can spend all day in a bookstore and only come out with one or two books.