The library is free to all, but this is really a working library and not like the museum in Grand Rapids. The library that is open to the public has a handful of exhibits that are on loan from the primary museum. If you are in the area and enjoy presidential history you should swing by. It is about a 30 minute time spend, so something nice and educational as you are hitting up Ann Arbor. I just would temper your expectations since this is really a small satellite library compared to the larger museum a few hours away.
My wife and I visited here in the morning and went to the Gerald Ford Museum in Grand Rapids later in the day. We spent about an hour at the Library and enjoyed it.
The Library is like a Reader’s Digest version of the Museum but with a greater emphasis on Ford’s connections to the University of Michigan.
If you’re not going to Grand Rapids then I highly recommend visiting here. If you are, I view the Library as optional since the Museum is much larger and more informative.
Stopped here on our quest to finish all of the Presidential libraries. Headed to Grand Rapids museum next. The library has a small exhibit on his life and a short video you can watch. It is worth a quick stop but the museum is much more in depth.