FIDDLER ON THE ROOF or 42nd STREET.
I know my grandmother would HATE HAIRSPRAY. Too flashy, and a bit too loud. "You Can't Stop The Beat."
I'd go with 42nd STREET. Lots of older showtunes she would recognize.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle