I’ve been doing this for over a decade now. I don’t use a thumbdrive though, I just email myself the thing I need to print. Go to library computer, log in to email, print right from there. Each page is 10 cents at my local branch.

Also, a lot of libraries will provide you with a “guest pass” so you can use the computers even if you don’t have a library card. 10/10 highly recommended.