“Here You Come Again” and “On Cedar Street” are very different new musicals about people who are unmoored and seek companionship to make it through.There is little to be gained from getting overly attached to source material. When a story told first in one form is adapted into another, it becomes a different creature — in the details and sometimes the broad outlines, too. So it goes with art; so has it ever gone.And yet I ask for a special dispensation in the case of the new musical, “On Cedar Street,” onstage through Sept. 2 at the Berkshire Theater Group’s Unicorn Theater in Stockbridge, Mass. The show is inspired by Kent Haruf’s slender final novel from 2015, “Our Souls at Night,” about how two widowed, small-town neighbors, Addie and Louis, gingerly find their way into each other’s lives after she proposes a remedy for their loneliness: that they start sleeping together platonically, for conversation and companionship.The book is a quiet, gentle thing, and it takes its time, layering in the details of Addie and Louis’s pasts and presents. Each has been lonely since long before their spouses died: his marriage marred by a scandalous affair, hers numbed by the death of a child. When Addie’s young grandson, Jamie, comes to stay with her, he’s lonely at first, too, and scared of the dark.But the novel’s forlorn heart is nowhere to be found in “On Cedar Street,” which has a book by Emily Mann; music by Lucy Simon (“The Secret Garden”), who died last October, and Carmel Dean; and lyrics by Susan Birkenhead. Directed by Susan H. Schulman, who staged “The Secret Garden” on Broadway, the musical presents Addie (Lauren Ward, in excellent form) and Louis (Stephen Bogardus, not quite disappearing into the role) as essentially fine with being alone, despite Addie’s comic difficulty with sleeping solo, which we witness in her toss-and-turn opening number.“I prefer the single life,” Addie and Louis sing early on, and though they’re skittish about getting romantically involved, they recognize that that’s exactly what they’re doing. Addie didn’t pick her one hot widowed neighbor for nothing. Like the middling Netflix film adaptation of the novel, starring Jane Fonda and Robert Redford, this production is definitely a beautiful-people incarnation of the tale.The ache of aloneness is gone, though, and with it the sense of two people cautiously choosing each other, trying not to unduly disturb their respective ghosts. And despite a physical design that’s all patchwork and wood, evoking a kind of sun-dappled Middle America, “On Cedar Street” has mostly discarded the straitening social pressure that Addie and Louis, in the novel, are rebelling against — taunting the local gossips by choosing happiness. (The set is by Reid Thompson, projections by Shawn Edward Boyle.)“On Cedar Street” skitters along, too busy for depth. At 105 minutes, it feels both scant and overcrowded, with narrative context pared away to make space for inorganic plot lines that seem like bids for timely social resonance: one involving a dangerous drought and another a left-winger-vs.-right-winger battle between Addie’s friend Ruth (Lana Gordon) and her neighbor Lloyd (Lenny Wolpe).Ruth serves one laudable new purpose in the musical, though: urging Addie to stand up to her grown son, Gene (Ben Roseberry), who treats her abominably and gets away with it because he blames himself for the accidental death of his sister when they were children. With his pain approximately one cell beneath the surface of his skin, he is forever ready to burst into emotionally lucid song.But Jamie (Hayden Hoffman), Gene’s 8-year-old son, is missing the tender vulnerability that the story needs from the child. That isn’t the fault of the actor; a high school student, he is simply too old for the role. Jamie’s dog, Charley, is played by a sandy-furred stage veteran named Addison. (Animal direction and training are by William Berloni; Rochelle Scudder is the dog handler.)The score, which includes additional music by Deborah Abramson, is a mixed bag stylistically. Much of the music is lovely, but almost no songs get the affective underpinning from the show that would make them land with any impact. The closest it gets to poignant is “The Girl We Were,” with strings underneath Addie’s remembrance of the passionate soul she used to be. (Music direction is by Kristin Stowell.)It’s Charley, ultimately, who elicits a moment of genuine emotion toward the finish of “On Cedar Street” — an overly neat ending (albeit an improvement on the novel’s) orchestrated by way of the drought plot line. A forest fire is involved, which might seem terribly of the moment, but then again so is loneliness.This spring, the U.S. Surgeon General released a report titled Our Epidemic of Loneliness and Isolation, warning of the need for social connection and the dire harm that its absence can bring. Addie, Louis and Jamie are prime examples — first of the ailment, then of the cure — if only “On Cedar Street” would let them be.Kevin (Matthew Risch) and Dolly (Tricia Paoluccio) in “Here You Come Again” at Goodspeed Musicals’ Terris Theater in Chester, Conn.Diane SobolewskiLoneliness is far more top of mind in the hallucinatory new jukebox comedy “Here You Come Again,” running through Aug. 27 at Goodspeed Musicals’ Terris Theater in Chester, Conn. The mind in question is barely hanging on.Kevin (Matthew Risch), an aspiring comic, has left New York for Texas in the early, planet-on-pause days of the pandemic. In May 2020, he is isolating in the attic of his childhood home. (The set is by Anna Louizos.) Pictures of his idol, Dolly Parton, hang on the wooden walls; downstairs, his parents watch Fox News. On the verge of being officially dumped by his hedge-fund-guy boyfriend back in Manhattan, Kevin is feeling fragile.But when he wakes to find Dolly (Tricia Paoluccio) in the room with him, he is less comforted than confused.“Hey, little buddy,” she says, with the beneficence of a Tennessee guardian angel making a surprise appearance. “I’ve been keeping my eye on everyone during the pandemic, and I could feel your need for some extra help.”This phantasmic Dolly is a charmer, and in her sparkles and stilettos and butterfly sleeves, she makes sense as the hero of a pandemic musical. (Costumes are by Bobby Pearce.) The real Parton spent the spring of 2020 donating to coronavirus research and reading bedtime stories to children online. The Dolly here is similarly generous, singing more than a dozen numbers: “Love Is Like a Butterfly,” “Jolene,” “I Will Always Love You” and other hits. (The music director is Eugene Gwozdz.)Paoluccio, who wrote the musical’s book with Bruce Vilanch and the show’s director-choreographer, Gabriel Barre, is a fun, fluid Dolly, bubbly and confiding. Because this Dolly exists in Kevin’s imagination, she doesn’t have to match the real one precisely, but she is close enough. One caveat: Paoluccio goes distractingly hard on Dolly’s sometime tendency to pronounce “s” like “sh.”It is Kevin’s story, though, and its telling needs more balancing and tightening. Unmoored from the life he’d been living and the home he’d made before the world abruptly got small, he is awash in self-pity — an unappealing quality when humor isn’t there to buoy it. The show also needs grounding in a reality outside the attic, to give it the emotional gravity it wants; the offstage voice of Kevin’s mother (Risch) could provide that if she were played straight rather than as a caricature.In its current state, “Here You Come Again” is unpolished, but Parton’s music makes it an easy good time. That, and Dolly’s company — even if we’re imagining her, too.Here You Come AgainThrough Aug. 27 at the Terris Theater, Chester, Conn.; goodspeed.org. Running time: 2 hours.On Cedar StreetThrough Sept. 2 at the Unicorn Theater, Stockbridge, Mass.; berkshiretheatregroup.org. Running time: 1 hour 45 minutes. More