We certainly are in Iowa. The rolling fields of “American Gothic,” writ large on a mural across the back wall of the Guthrie Theater stage, tell us that.

Even the buildings of River City in Todd Rosenthal’s set are dappled to blend into the landscape. And if we still hadn’t gotten it, two actors frame themselves in a stage cameo of Grant Wood’s painting during “Iowa Stubborn.”

That bit was actually pretty funny, in a spoof sort of way, and that frolicking sensibility is the best part of director John Miller-Stephany’s production of “The Music Man,” which opened Friday on the thrust stage.

Miller-Stephany, with choreographer Joe Chvala and music director Andrew Cooke, paint the colors of some spectacular stage imagery. Chvala, as always, has everyone moving with grace and rhythm. Sonically, Cooke seems right on point with his singers.

With corny winks and properly garish costuming of the period (Mathew J. LeFebvre), the insular rubes of Meredith Willson’s hometown strut like cartoons while an outsider drops in with a pitch for their money and their hearts.

In the bargain, of course, it is the hustler who gets hustled. Prof. Harold Hill is the salesman who gets his foot caught in the door and ends up a changed man. He came for money but found love with Marian Paroo.

It is in the human portrayals that the staging suffers.

Danny Binstock’s Harold Hill has the art of the con man, but not the science — an irresistible charisma, a voice or manner that effortlessly entrances us. Binstock, a fine song and dance guy, labors mightily and never achieves the mesmerizing charm that defines a character who can run a scam in his sleep.

Stacie Bono doesn’t have much luck, either, finding a chemistry with her character, the feisty and stubborn Marian the librarian.

She’s a bit brittle and he’s faking it, so despite what they sing in “Till There Was You” — gorgeously, it must be noted — it is hard to hear those bells ringing and see the birds winging in their relationship.

Never will you see a more forceful characterization of Mayor Shinn. Peter Thomson attacks a role that’s often a bumbling knucklehead — a satire of government. Thomson uses Shinn’s verbal tics as fuel for a volatile temper, and by sheer force of personality, he becomes the mightiest foe of Harold Hill.

Thank goodness for the barbershop quartet (Jacey Squires, Joel Liestman, Robert O. Berdahl and James Ramlet) to leaven that bombast. Liestman is subbing for T. Mychael Rambo, out with a foot injury.

If there is real heart in this production, it comes from the children. Soren Thayne Miller sings the heck out of “Gary, Indiana,” and Natalie Tran as Amaryllis generates more charm per square inch than any actor on stage.

In fact, one of Miller-Stephany’s successes is his focus on the generation gap. The parents, led by Shinn, are old and childish; the kids, led by Brandon Timmons’ Tommy, are young, idealistic and restless.

If only Binstock and to a lesser extent Bono could slide into the sweet sense of grace that makes their characters great — and reveal something new about this transformational relationship.

So sleep through the love scenes and wake up for the pageant — it’s quite a show.