An aged odd couple takes on the Appalachian Trail with predictable results in Ken Kwapis’ adaptation of Bill Bryson’s 1998 book. Innocuous but insubstantial, “A Walk in the Woods” serves mostly as an engaging soft-shoe routine for veterans Robert Redford and Nick Nolte, even if the actors are shod in hiking boots.

Redford stars as Bryson, a travel writer who’s introduced taking inane questions on a Boston TV talk show. Back home with wife Cathy (Emma Thompson), he reluctantly attends a funeral of a friend that only reminds him of his own mortality. The upshot is that he decides to walk the 2,100-mile Appalachian Trail, a venture his spouse first argues vehemently against and then accedes to reluctantly only if Bryson doesn’t make the attempt alone.

When all the friends he asks decline, all seems lost until Bryson gets an unexpected call from Stephen Katz (Nolte), an old buddy from Iowa whom he hasn’t talked with in years. Sam invites himself as Bryson’s companion, and Bill reluctantly agrees. But when Katz shows up, he’s a grizzled, overweight, womanizing alcoholic who stumbles around helplessly and claims to have to eat every hour or so for medical reasons (the last disappears pretty much instantly). Nonetheless Bryson has no other option, so off they go to Georgia to begin the long northward trek.

What follows is a serious of comic episodes, many of them of sitcom quality (an early encounter with Mary Ellen, a motor-mouthed egomaniac played by Kristen Schall, lots of slapstick pratfalls, a stop during which would-be lothario Stephen hooks up with a chubby woman and has to flee her jealous husband through a too-small window, an unfortunate incident with a bunk bed in which Katz insists on the top mattress), juxtaposed with more serious, ruminative moments in which the two men bond over old times and present crises. Along the way there are plenty of opportunities for widescreen shots of the natural surroundings, courtesy of cinematographer John Bailey, and a stream of wry observations by Bryson, delivered by Redford with a twinkle in his crinkled eye. (Bryson might fall and stumble a lot, but except in social functions like a funeral, he’s rarely at a loss for words.)

Put it all together and you have a package that should appeal to more mature audiences while boring younger ones to distraction—appealing to a graying viewership in much the same way that British fare like “The Best Exotic Marigold Hotel” has. There are even the same sorts of “naughty” moments sprinkled throughout the narrative, carefully calibrated to induce blushes and embarrassed giggles without going too far.

But the key, of course, is the interplay between Redford and Nolte, two familiar faces whose very presence encourages a warm reception. They play well off one another, with Redford happily serving as straight man to the bedraggled Nolte, whose gravel voice and hangdog face are almost too perfect a fit with the roguish Katz. Kwapis is content to give both of them full rein, allowing the actors to go through their paces without appreciable interference from him. He apparently followed the same tactic with Thompson and Schaal, who both deliver strongly and Mary Steenburgen, who plays a hotelier who gently comes on to Bryson toward the close of the trek. (A moment involving her quietly demented mother, however, comes across as rather weird.) There’s a nice cameo by Nick Offerman as the deadly earnest salesman who sells Bryson his camping equipment.

It will hardly come as a shock that after their trek is over Bryson and Katz have revived their old camaraderie, or that despite protesting throughout the journey that he wasn’t undertaking the walk in order to collect material for a book, Bryson nevertheless sits down to write one. That’s of a piece with the entire movie, which proceeds genially step by step without ever going off in a remotely surprising direction. The stars make agreeable walking companions, but they don’t take you anywhere particularly memorable.