Donald Sutherland and Helen Mirren spend most of this heart-tugger driving around in an exhaust-spewing forty-year old Winnebago. The script that is their other vehicle is a rusty, ramshackle thing too. Of course any movie that stars these two is bound to have a few pleasant moments, but even so charming a pair cannot save “The Leisure Seeker,” which might have been titled “On Golden RV.”

The set-up is a simple one. As her husband John (Sutherland), a retired English teacher, sinks deeper into Alzheimer’s, Ella (Mirren), his chatty wife of half a century, has decided they should dust off the old RV, which she named the Leisure Seeker, and take one last trip in it. The destination will be the Key West home of Ernest Hemingway, whose literary skill John has long adored. The drive from their Massachusetts home will be long and arduous, but Ella has brought along a projector and loads of family slides they can watch outdoors at the parks where they spend the nights. Other campers will often join in the viewings.

Speaking of family, the impromptu trip leaves the grown Spencer children, Will (Christian McKay), who’s apparently an unmarried baker or florist, and college professor Jane (Janel Moloney), back home wondering where the old folks are and worrying about how they’re faring on the road. It appears that they were on the brink of installing their parents in medical facilities, John for the obvious reason and Ella because she’s obviously not well, as her wig, pill-popping and occasional propensity to collapse all indicate.

What follows is a highly episodic road movie, in which Ella is prone to babble on to strangers about her life with John and he is inclined to regale them with facts about Hemingway or Herman Melville. It should be noted that his forgetfulness is occasional, depending on the momentary needs of the script. At times (as when running into a former student), he’s completely lucid, while at others he’s simply childlike and at still others gloomy about his ability to remember anything. Ella is solicitous, of course, but is also given to periodic bouts of anger at his condition.

One thing that certainly joins them is jealousy at the thought the other might have been unfaithful. John periodically accuses his wife of having kept up the acquaintance of her first boyfriend Dan, while Ella responds with fury when she suspects a dalliance John might have had years ago. Naturally, though, their respective outbursts are played for comic effect, and their love for one another overcomes all obstacles.

Apart from that, “The Leisure Seeker” consists of a string of predictable episodes along the way to Florida. They spend a night in a ritzy hotel; they encounter a couple of thieves (Chekhov’s old maxim about a gun shown early is thus followed scrupulously), they run into a Trump campaign rally (the time is the summer of 2016), and so on. They finally reach the Hemingway house, but it proves a disappointing tourist trap, and the place where reality strikes home for them both. A predictable conclusion indicating that they’ll never be separated closes things.

Throughout Sutherland and Mirren work overtime to extract some charm from the feeble material, and being old pros, they succeed more often than the makers had any right to expect. The punctuations by Moloney and, especially, McKay are, by contrast, rather irritating, and the supporting performers are generally weak, with virtual cameos by Dana Ivey and Dick Gregory particularly sad. Cinematographer Luca Bigazzi, however, uses the locations to reasonably good effect, though editor Jacopo Quadri is unable to inject much verve into the proceeding beyond what the stars bring to their scenes.

This is the first English-language film from Italian director Paolo Virzi, and it singularly lacks the spirit of his previous road movie, “Like Crazy,” which followed two women escapees from a state-run mental facility. This is Hallmark Hall of Fame moviemaking to the highest degree, and one suspects that while some quite elderly viewers might enjoy its mildly naughty spurts (even as they might find the constant intimations of mortality a bit unsettling), most viewers will rightly dismiss it as saccharine piffle unredeemed by its two talented stars.