Grant Harrison and Tana Hicken in ‘4000 Miles’ at Studio Theatre. (SCOTT SUCHMAN)

Please give a warm welcome to Amy Herzog, a playwright of distinction whose rich portfolio you’ll want to get to know. Shaped by deft observation and psychological texture, her work has begun to appear on the schedules of the nation’s savvier companies, and at last is getting an airing here, in Studio Theatre’s regional premiere of her smart and penetrating “4000 Miles.”

The comedy-drama, directed by Joy Zinoman, Studio’s founder and an accomplished shepherd of intimate-scale theater, is a skillful joining of loose ends. The dangling threads in this case are Grant Harrison’s Leo, a scruffy cyclist trying to find his bearings on a cross-country road trip, and Tana Hicken’s Vera, a crotchety lefty teetering on the brink of infirmity in a rent-controlled apartment in Greenwich Village.

The manchild and his step-grandmother meet at the center of Herzog’s play, which as much as anything is about the surprising contours one adjusts to on the circuitous paths to commitment and purpose. What’s admirable about “4000 Miles” is also what’s elusive: It’s difficult to pin down exactly why it’s so darn appealing, aside from the simple pleasures derived from getting to know Leo and Vera. Come to think of it, they endear themselves to us in much the same way that they grow on each other.

The assurance with which Herzog conjures characters recalls dramatists such as Lanford Wilson and Michael Weller, who in works such as “Fifth of July” and “Spoils of War” dealt as Herzog does here with the interplay of progressive political ideals in the lives of people who aren’t at peace, with themselves or with one another. Still, from other recent works you can tell hers is a voice-in-progress. In her absorbing “The Great God Pan,” she compromises a good idea — about a man tortured by the intimation he was molested as a boy — with an overly schematic structure. And in her Paris-set thriller “Belleville,” soon to end a run at New York Theatre Workshop, a surfeit of writer-y manipulation dilutes an intriguing approach to a conventional genre piece.

“4000 Miles” is her most satisfying play to date, in part because the plot feels so unencumbered. Leo’s growth over the course of his stay in Vera’s flat — rendered by set designer Russell Metheny as one of those cozily utilitarian, book-lined New York apartments — is such a seamless emergence that you hardly notice it’s happening. The lanky Harrison is completely convincing as a guy who lives in the moment, not because it’s a philosophical choice, but because he has simply never been able to notice anything going on more than three feet in front of him.

The play takes its name from the bike trip Leo has been on with his ill-fated friend, Micah, from St. Paul to New York City, where his outdoorsy girlfriend, Bec (a touchingly mournful Heather Haney), is studying. Clueless Leo turns up at Vera’s threshold before dawn — Vera’s slog to the door, a feature of Lincoln Center Theater’s 2011 production, has been cut in Zinoman’s zippier treatment — and soon enough, the easily irritated Vera is washing out his underwear and lending him money for trips to the climbing-wall gym.

Hicken, who is 68, is a tad too hardy for the octogenarian Vera, but her portrayal nevertheless captures Vera’s grit, the bohemian life force that belies Vera’s failing memory and penchant for worn-out cardigans. (Costume designer Helen Huang gets everything right, down to Leo’s weathered spandex.) Vera is a character who clearly fascinates the playwright, because she also turns up in “After the Revolution,” Herzog’s earlier drama about a family of East Coast radicals. Here, Vera is the link to what “4000 Miles” enshrines as an era of courageous political independence, a time of activism when progressives of her ilk were branded as “Commies” — and they would have worn the label proudly.

“A lot of people were Communist — it was like recycling or whatever,” Leo declares defensively, after the young lady he’s brought back to the apartment one night (played by the infectiously vivacious Annie Chang) recoils at the Marxist books that fill Vera’s library. There’s a wisp of condescension — albeit affectionate — in Herzog’s characterization of Leo; you can’t help but laugh at the gauche inappropriateness of his calling an old lady “Dude.” That’s the way of this sheltered generation, the play seems to be telling us. At the same time, though, Vera reminds us, as she casually refers to her shacking up with Leo’s grandfather, that once it was Vera’s turn to impose her manners and mores on the world.

The sharing of close quarters brings out the best in Leo and Vera, without thoroughly erasing what renders them fallible and, one imagines, what would make either of them tough to live with. The sweet speech Leo practices for Vera at the end of the play reveals that he may be ready to abandon the cocoon in which he’s traveled all those miles, just as, in Herzog’s wise prescription, Vera experiences a meaningful cracking of her own shell.

4000 Miles

by Amy Herzog. Directed by Joy Zinoman. Set, Russell Metheny; costumes, Helen Huang; lighting, Daniel MacLean Wagner; original music and sound, Lindsay Jones. About 1 hour 40 minutes. Through April 28 at Studio Theatre, 1501 14th St. NW. Visit or call 202-332-3300.