Actors of a certain age love to play wild-eyed eccentrics. Sometimes the ploy works out to everyone’s benefit. Peter O’Toole, who’s especially good at it, had a field day in “The Ruling Class” and “My Favorite Year” (among others), as did Alec Guinness in “The Horse’s Mouth” (1958) and even George C. Scott in “They Might Be Giants” (1971). More often, though, the effort turns out to be a lot more enjoyable for the actors than the audience.

That’s the case with Mike Cahill’s feeble little comedy, in which an unkempt, thick-bearded Michael Douglas plays Charlie, a recently-released patient in a California state mental hospital who returns home to his bewildered daughter Miranda (Evan Rachel Wood) with a plan to find a buried Spanish treasure. Charlie’s always been an unreliable fellow—an ex-hippie type and wannabe jazz bass player whose shenanigans drove away his wife—and Miranda, who’s quit school and taken on a fast-food job to save the house, initially dismisses his quixotic quest. But her affection for him eventually wins out, and eventually the two are following the clues the old man’s gleaned from maps, records and diaries through the California landscape, eventually winding up at a Costco, where Charlie’s certain the loot is buried beneath a cement floor. Enlisting an old pal of Charlie’s with a past in security work, they break into the store and through the floor, though—as might be expected—things don’t turn out exactly as hoped.

It has to be said that though Douglas obviously relishes the opportunity to wear rumpled clothes (sometimes rather few of them) and play the wise fool, he doesn’t go as far as he might have done—which is certainly a blessing. But “King of California” nonetheless suffers from an excess of quirkiness, which extends not only to Willis Burk’s turn as Pepper, the befuddled guy Charlie entices into the scheme, but to David Robbins’ guitar-and-banjo flavored score, which tries to be way too cute.

On the other hand, the picture is really weighed down by Wood, whose cheerless performance might have been intended to provide ballast but acts more like a heavy anchor. The role would have been a difficult one for any actress, but she’s too inexperienced to find the proper note for it. And technically the production is pretty flat, with James Whitaker’s cinematography very plain indeed.

The movie includes Alexander Payne and Michael London, the creators of the brilliant “Sideways,” among its producers. That’s yet another sign of the increasingly fallibility of the Payne coterie—he and writing partner Jim Taylor, after all, also worked on the awful script of last summer’s “I Now Pronounce You Chuck and Larry.”

However much Douglas might have savored making it, this “King” deserves no royal welcome.