Regarding downloading an audiobook for an MP3 player, you could accomplish this using OverDrive for Windows; however, please note that eventually we will be sunsetting Classic OverDrive and you will not be able to download audiobooks to your computer to transfer to an MP3 player. While there is not yet a firm timeline in place for this, I do believe it will be sooner rather than later.
My suggestion would be to invest in devices that support the Libby app.
Don't hesitate to speak with a librarian if you have questions. 603 876 4479