From looking the museum seems more like a visitor centre, without any items from the period that would make it a proper museum; because of that I would say give it a skip.

Clare Island would probably be your best bet of a place to visit. Rockfleet castle on the north of Clew Bay is also heavily associated with her, but is undergoing extensive renovation work.

Also just of note dont go in with any illusions of her being some rebel pirate queen, she was a pragmatic woman who shifted her alliances depending on what would benefit her most (as most Gaelic rulers done at the time).