Check out the Metropolitan Museums’ Thomas J. Watson Library http://libmma.org/portal/museum-archives/
The Met has started to make some of their institutional archives available to the public; some online. I don’t see actual exhibition files, just a list, but they may be a go to source for what to include.
At the institution I work at, I have yet to tackle the culling of old exhibition files.
Shannon Lindridge, registrar