June Schreiner as Muriel McComber, left, and William Patrick Riley as Richard are shown in Act III of Eugene O'Neill's “Ah, Wilderness!” during a final dress rehearsal at Arena Stage. (Nikki Kahn/THE WASHINGTON POST)

At the cozy end of a summer day’s lark — a long day’s lark at that — a contented dad sits in his easy chair, across from a beaming mom, and reflects on the many blessings that have been bestowed upon them both.

“From all accounts, we seem to be completely surrounded by love,” the father says. “It’s been a good day, Essie. A good day.”

This gooey takeaway is essentially what you’re left with after the nearly three hours you invest in the sweet, low-grade kerfuffles spelled out in Eugene O’Neill’s 1933 valentine to hearty turn-of-the-20th-century American family life, “Ah, Wilderness!” Nothing’s gonna harm you in this rare incidence in O’Neill’s stormy oeuvre of a play in which everything just kind of works out for the best.

It’s hard, therefore, to argue with any of the kindnesses outlined in Arena Stage’s first-class production, expertly cast and assembled on the Fichandler Stage by director Kyle Donnelly. It’s also hard to get overly excited about them.

With the opening of “Ah, Wilderness!”, Arena launches a sampling of this cornerstone dramatist’s work in conjunction with the Shakespeare Theatre Company. Still to come is Arena’s revival of “Long Day’s Journey Into Night,” and the Shakespeare’s staging of the far less frequently revived “Strange Interlude.” A selection of plays inspired by O’Neill will be interspersed, along with readings, lectures and panel discussions.

The calculation for placing “Ah, Wilderness!” in leadoff position may have been that its wholesomeness lays down the cushiest welcome mat; it’s as safe for your system as a digestive biscuit, and as well-made as a Model T. (Recall, too, that to open Arena’s refurbished complex on Sixth Street and Maine Avenue SW, artistic director Molly Smith chose another item from the nation’s breakfront of burnished classics: Rodgers and Hammerstein’s 1943 “Oklahoma!”)

Smith earned every drop of ink in that titular exclamation point through her scrupulously affectionate staging. Donnelly proves just as attentive to the more wistful exuberance represented by her play’s title. I doubt we’ll see a version of this light comedy again that attaches actors’ temperaments so acutely to their characters’ personalities. The outstanding portraiture begins with the surefire anchoring by William Patrick Riley, who plays the one absolutely pivotal role, that of young Richard Miller, the Yale-bound, would-be rebel, who sulks about the girl he loves and scandalizes his mother with anarchist sympathies and quotes of the work of the brazen Oscar Wilde.

Richard, perhaps an idealized representation of O’Neill himself — he based the “Ah, Wilderness!” family on that of one of his childhood friends in New London, Conn. — is our touchstone. His outsize disdain for his parents’ wisdom and his siblings’ presence magnifies our feelings of well-being here: We watch with knowing amusement as Richard endearingly struggles to establish his autonomy and navigate the choppy channels of young adulthood, notably through his dealings with the opposite sex.

“Ah, Wilderness!” chronicles a Fourth of July — what’s more Norman Rockwell America than that? — in the life of the Miller clan, ensconced in their airy New England homestead, with lobsters on the stove (this is the seaside) and a few minor issues bubbling up to the surface. Oh, there’s some squabbling between newspaper publisher Nat Miller and wife Essie, portrayed by Rick Foucheux and Nancy Robinette, both in wryly fine form. And kids will of course will be kids, especially the rascally youngest, played here with so much carbonated charm by Thomas Langston that you’ll want to see if they’re selling some of his impish energy at the concession stand.

Only in the subplot of the short-circuited courtship of Nat’s disconsolate sister Lily (Kimberly Schraf) and Essie’s drunk of a brother Sid (Jonathan Lincoln Fried) is there the suggestion of deeper emotional scars. Fried vies with Riley for top acting honors on this occasion; the suggestion subtly but persuasively hangs over his portrayal that despite his multiple offers of marriage to Lily — who declines because he drinks — Sid is more than a little sexually ambivalent. The lengthy dinner scene in Act 1 rides on the comic travesties of this stumbling Sid, whose embarrassing antics at the table are encouraged by the Millers’ giggles.

This is 1906, after all, when a drunk uncle was sent to bed rather than rehab, and — in O’Neill’s judgment at least — the womenfolk seem consigned either to the categories of refined and marriageable, or coarse and loose. (Richard repairs that night to a disreputable bar, where to his terror he’s snared by a hooker, played by the terrific Pearl Rhein, painted by the playwright as a most stereotypically craven lady of the night.)

The prostitute’s polar opposite, Muriel — the becoming girl of Richard’s dreams — is played with poise and elegance by June Schreiner, the Ado Annie of Smith’s “Oklahoma!” Here, in her one major scene with Riley’s Richard late in the play, on a moonlit beach alluringly lighted by designer Russell Champa, she proves once again to be a total natural.

So much polished work has gone into Donnelly’s production, down to Nan-Cibulla Jenkins’s prim period costumes, that you might at isolated moments be convinced that this July 4th is actually of some consequence. Those merely wanting to slip into the nostalgic tempo O’Neill is tapping will be the spectators most enthralled by the play’s tasteful music and sedate musings.

Ah, Wilderness!

by Eugene O’Neill. Directed by Kyle Donnelly. Sets, Kate Edmunds; costumes, composer and music direction, Michael Roth; hair and makeup, Christal Schanes. With Davis Chandler Hasty, Talisa Friedman, Leo Erickson, James Flanagan, Allison Leigh Corke. About 2 hours 45 minutes. Through April 8 at Arena Stage, 1011 Sixth St. SW. Visit www.arenastage.org or call 202-488-3300.