I think it’s probably best for extended runs such as an exhibition to get things as minimal as possible. Connections to the web or PC/MAC driving things are not a really viable solution given the duration of a show, the range of people responsible for the daily start of the show etc. Best to establish a ‘turn it all on and away it runs’ option. An AppleTV will need a source, either a playlist which loops on iTunes running on a computer or the equivalent on Vimeo say where you set up a video which repeats the video over for the daily duration of the show. This introduces some fragility however, online access and the daily start being more complex. A player is more robust and straightforward.
Be aware you can set up a Keynote presentation to show your images and videos, title cards etc and it’s very controllable. It can export a fully configurable video as well, full HD even ProRes 4444. A lot of filmmakers use it for title sequences and cut them into their FCP projects.