As many great actors age, they gradually shift into playing grumpy old men, as exemplified by Robert Duvall’s Oscar-nominated turn last year in The Judge. Robert Redford, on the other hand, seemingly wants to defy both Father Time and Mother Nature as he nears 80. Months after perhaps his best role ever in J.C. Chandor’s All Is Lost, he follows it with another physically challenging role as a man determined to hike the entire Appalachian Trail in A Walk in the Woods. However, those who enjoy watching grumpy old men will have their opportunity in Walk as well, as he takes the quite irascible Nick Nolte along for the trek.

Redford originally optioned the rights to Bill Bryson’s memoir of the same name a decade ago, enivisioning it as a vehicle to reteam him with Paul Newman. Sadly, Newman died before that could occur, and the project went on the back burner for a while. Fortunately, Redford has gotten the movie made while he’s still physically up to it and managed to secure the services of a co-star who is able to stand up to him on screen. Unfortunately, A Walk in the Woods seems like more of an afternoon stroll down a nature trail than a cross-country hike worthy of a memoir or a movie.

The screenplay has taken several liberties with Bryson’s original memoir, most notably in aging the characters by about three decades (Bryson was 44 when he made his hike). The idea of a couple of septuagenarians going on a 2,000 mile, six-month hike is considerably more daunting than that of a pair of 40-somethings doing the same thing. The other major change has to do with Bryson’s motivation. The actual Bryson, an accomplished travel writer, saw the trip as merely one more subject for a book and had accepted an advance for it. The celluloid Bryson, as played by Redford, sees his literary career running on fumes (he’s spent the last five years writing forwards for other people’s works) and views the hike as a personal challenge that will hopefully motivate him.

While Redford’s Bryson won’t be talked out of his quest by his loving yet sensible wife (Emma Thompson), she does at least succeed in getting him to agree to take along a hiking companion. After all his acquaintances turn him down, Bryson is stunned to get a call from someone he hadn’t invited, Stephen Katz (Nolte). He and Katz had traveled through Europe some four decades earlier as free spirited adventurers but lost touch as Brysone met his wife and put down roots.

It seems like Katz, however, has never settled down, and his life is a series of failed relationships and battles with the bottle and the law. Although he tells Bryson he merely wants to reconnect, Bryson and the audience learn he has an ulterior motive: to lay low and avoid a 30-day prison sentence. Still, despite his personal problems (which rarely merit a mention until the obligatory bonding scene late in the movie) and a litany of weight and health issues, Katz never really seems to slow Bryson down unless or until the plot demands it.

Viewers’ natural tendencies are to view A Walk in the Woods as a male, senior citizen version of last year’s Reese Witherspoon film, Wild, but the two share little other than star power and occasional scenery. Wild gave viewers a great feel, both for the hiking experience, with its splendor and danger, and the inner demons that drove the main character. Woods, on the other hand, pays lip service to the characters and their motivations and comes across more like an extended sitcom episode in which the two stars exchange scripted quips for hundreds of miles.

Certainly, Nolte and Redford are up to the task. They have an easy-going chemistry together, and each is playing a character well within his wheelhouse. However, they seem to be skimming the surface here. Redford in particular is a bit disappointing, not because of anything he does, but because the script lets him down. The actor is a noted environmentalist and gets the opportunity to deliver a couple of good speechlets, one about the disappearance of the chestnut tree, but the essence of Bryson’s memoir, the actual author’s wit and keen observations, are completely missing here, in lieu of canned sitcom laughs.

When the characters aren’t talking, they are engaging in equally typical sitcom shtick, such as an encounter with bears and another encounter with an even more dangerous form of wildlife, an angry husband. The latter is associated with an overweight woman Katz meets and flirts with at a laundromat and engages in the lowest of lowbrow humor (trying to remove her panties that are caught in the dryer, Katz refers to himself as a “pantyologist”). Of course, the script contrasts this with the upstanding Bryson, who has his own temptation in the form of motel owner Mary Steenburgen, who makes it clear she is very much available.

A Walk in the Woods was directed by Ken Kwapis, whose work has mostly been in television, and he seems most comfortable with this type of light banter and crude slapstick, mixed in with a handful of extraordinary landscape shots. In the hands of lesser actors, Walk could have turned into a complete disaster. As it is, the movie still comes perilously close to the old adage about paying to see a great actor read a telephone book.

Like a television episode constrained by a 30 or 60-minute time limit, A Walk in the Woods ends rather abruptly and, frankly, somewhat arbitrarily. Without giving too much away, it’s safe to say that the film makers indeed went for a safe, and highly predictable ending that feels nowhere near as cathartic as watching Wild did. On the other hand, though, audiences will certainly have gotten what they paid for here, as the two stars are onscreen and dominating for nearly every moment of the movie.