As undemanding fluff goes, "Moon Shine!" at the West Valley Playhouse has its moments. Whether they carry this country-flavored tuner about a driven ad exec and the heir to a Texas animal-food empire is provisional.

Written by Mary Willard, with songs by Grammy winner Marty Stuart, "Moon Shine!" is pure sitcom in its premise. Jordan St. John (Adreana Betancourt) is everyone's doormat at the Grey, Green & Gold Advertising Agency, particularly Keenan Keveevan (Anthony Liveri), her noxious superior.

After he steals her ideas, Jordan vows to become a ruthless user, as she admits to Zoe (Natasha Baumgardner), her aspiring novelist sister, and Kenny (Steve Ruggles), their flamboyant pal. Quicker than you can say "Working Girl," Griffin Evergood (Patrick Foley), the client Jordan hoped to impress, sashays into the Casa Luna Nightclub, his brothers in tow. Moth (David Columbo) is a starry-eyed match for Zoe; Caleb (Ben Rosenfeld) isn't drawn to girls. As for Griffin, according to Daddy's will he must marry by Nov. 22 or lose control of the business.

The ready-made sextet treks across L.A., where the same unemployed actor (Michael Jay Aronovitz) keeps turning up as their waiter, and Act 1 ends with everyone bound for Pancake City, Texas. Act 2 brings on the Evergood Ranch, where Uncle Pye (David Burr) quotes classics on the veranda and matriarch Christabelle (Nancy Solomons) prepares for the annual Big Hair Ball.

Stuart writes some bouncy numbers, especially the line-dancing trios for the Evergood boys, and the love songs warrant airplay. However, a repetitive sameness eventually develops, despite musical director Paul Taylor's zest, and Willard's book is wildly predictable and overextended.

Alas, so is director Jon Berry's production, skimpy by his usual standards. Choreographer Noel Britton fields a chorus of three women and one man, set designer Charles Hall's black curtains and facade are barely functional, and backfiring body-mikes defeat their purpose. They certainly tax the cast, likable enough but not always on the same page. Betancourt should relax, and Foley could be bigger. Their colleagues are game, though Solomons is short on bombast and Ruggles seems miscast, albeit in a role that could stymie Scott Thompson.

Trimmed by 30 minutes, more resourcefully executed, "Moon Shine!" could be a populist lark. At present, it's ultimately a dinner-theater entry, minus the meal.

By David C. Nichols