They’re just a couple of sway-backed, high-mileage actors, each a dozen years older than their characters and showing it.

They cuss and fuss and reminisce and make all the same mistakes Reese Witherspoon’s character made in “Wild.” And then some.

The annoying “trail mate” shows up at the right time, the fetching innkeeper a little later and the bear a little later still. All very predictable when you take “A Walk in the Woods.”

But God help me, I grinned from beginning to end.

Bill Bryson’s hiking the Appalachian Trail memoir becomes a Robert Redford/Nick Nolte vehicle, an amusing and light “Slightly Grouchy Old Men” aimed squarely at an older audience.

Redford is Bryson, an award winning travel writer reaching retirement age, and the age when you spend too much time going to friends’ funerals. On an impulse, he decides that this Appalachian Trail that runs through the woods in the New Hampshire town where he lives just might be one last challenge to tackle.

His wife (Emma Thomson) is not keen on the idea, but resigned to it. His son is full of the “at your age” warnings. And the hiking gear salesman/trail nerd (Nick Offerman, on the nose) sees him coming. No matter. Bill will get out there and see the forests, the eastern wild “while there’s still some left.”

But rounding up a peer to go with him gets nowhere, until his estranged hometown pal Katz (Nolte) gets wind of the quest. They once backpacked and bickered through Europe. But that was 40 years ago. Bygones, right? Let’s “sneak in one last adventure before it’s too late,” he growls, and Bryson agrees.

Here’s how Nolte steals the movie. He once voiced a bear in a cartoon. With good reason. He wears a fedora that could be a leftover prop from “Cannery Row,” which he filmed 30 years ago. He looks, shambles along and talks like a guy who has crawled in and out of the bottle, gargled with gravel and stopped way too many right hooks with his cheekbones. For decades.

Katz growls, grumps and slows the pair down. Every funny episode, like encountering the nerdy know-it-all (Kristen Schaal) that they then must ditch — lest she chatter-nag them to death — earns a “Can’t WAIT to read about this in the book” from Katz.

And an “I’m not WRITING a book” from Bryson.

Mary Steenburgen, every senior citizen comedy’s go-to love interest, is the twinkling owner of a trailside inn. Because that’s all this pretends to be, a codgerish-comedy. None of the profundity of “Into the Wild” or “Wild.” Whatever these two backpacking old men learn — and the puffy, pink Nolte/Katz seems to look healthier, the more miles they cover — it’s not deep.

But it is funny, and Redford, gracious as ever, makes a wonderful straight-man for a comic co-costar who has the face, voice and posture of a geezer who probably should have tackled this healing hike 20 years earlier.

MPAA Rating:R for language and some sexual references

Cast: Robert Redford, Nick Nolte, Emma Thomson, Mary Steenburgen, Kristen Schaal, Nick Offerman
Credits: Directed by Ken Kwapis, script by Rick Kerb and Bill Holderman, based on the Bill Bryson book.  A Broad Green release.

Running time: 1:44