Baaaaaad idea!!!
Do you get that I don't think much of the idea?
A blog has zero value for the type of information a theatre -- or any business -- needs to present.
A business should consider the front page of the website via the old "who, what, where, when, and why" mantra. Even if you get them that info via big buttons, it needs to be obvious how to get the info.
With a blog, are you planning on posting this information in every post? If so, why have the blog when you could just have a web page. If you're not going to post the info in every post, how does the customer locate the correct post to find showtimes? Ugh.
Now, there's no reason NOT to have a blog in addition to your basically static theatre information. A theatre blog is great for letting people know what going on around shows, or in the theatre, etc. I have a blog for our site on which I post construction pictures, short stories from around the theatre, etc.
Use a blog as an adjunct, not a replacement.
BTW, Wordpress works great.
Grandview Theatre Insight