Suburban theater companies are often frustrated in trying to find a Chicago venue where they can transfer successful productions and reach new audiences. The Ivanhoe Theater in Wrigleyville closed some years ago (it’s now a Binny’s liquor store), the Briar Street Theatre has been occupied by Blue Man Group for more than a decade, and the Royal George’s mainstage is booked up for the fall. So when Apple Tree Theatre in Highland Park decided to gamble on bringing its lovely, offbeat concept musical The Mistress Cycle to the city, it wasn’t easy to nail down a space.