HEROES OF THE FRONTIER

By Dave Eggers

Knopf, 385 pp., $28.95

Since his first book, “A Heartbreaking Work of Staggering Genius,’’ Dave Eggers has been obsessed by the alchemy of wonder and disaster aversion that makes a family.

It’s an understandable fascination in a writer who grew up too fast after a very adult disaster — his parents’s one-two deaths from cancer, which left him at 22 as primary caretaker for his 9-year-old brother.

In that memoir, Eggers described how he and his charge turned away from the Midwest blast site and went west, how California made hope possible.

Now, 15 years later, in “Heroes of the Frontier,’’ he has written a similar book, this time a novel and from a different angle and a different state.

Josie, the heroine of Eggers’s exuberant new work, is a separated mother of two on the lam with her children. She has lost her a thriving dental practice after a malpractice suit. Carl, her deadbeat, entitled ex-husband, has abandoned her and plans to remarry. She needs a second start.

So, without telling Carl, Josie heads for Alaska with $3,000 in cash and a vague plan of reuniting with an adopted sister. Her children — Ana, 5, and Paul, 8 — are cheered by this adventure. They are too young to feel their mother’s desperation, rattling through each chapter of this book like the dilapidated RV they drive.

“Heroes of the Frontier’’ is actually a series of restarts. Each chapter begins with a new scheme. Josie and the kids roll up to a new campsite, an abandoned cottage, or pass the day with another traveler who may bring them harm. By the chapter’s end, they’re furiously peeling off back onto the road, a step ahead of one firestorm or another.

Initially, the fury of motion in “Heroes of the Frontier’’ makes it feel like a classic road novel. Adventure and improvisation provide the internal combustion, and the episodic nature of incidents recall a more domestic version of “On the Road’’ — only here it’s a woman and her two children driving the tale, not women left behind while the men explore.

Squeezed into the down time of these adventures, “Heroes of the Frontier’’ chronicles Josie’s greater search for meaning, as a parent and as a woman. On each stage of her pilgrimage, Josie thinks harder about what it means to pass on life to the next generation, and what she wants now that Ohio is behind her.

“The best parents rise and fall like the sons and moons,’’ she excoriates herself, leaving a bar after a night of drinking cut short, as her sister begins to make out with a Leonard Cohen look-alike 40 years her senior. “They circle with the predictability of planets.’’

Not much later Josie’s thinking evolves. “We are better when we expect tragedy, calamity, chaos,’’ she surmises, remembering how a misdiagnosed patient led to the demise of her business.

And yet later, as they relax one afternoon, the kids shooting arrows and running in the woods, she comes upon a new epiphany: “It was only about making them loved in a moment in the sun.’’

Zooming in and out of Josie’s mind as she veers from one near disaster to the next allows Eggers to deploy his considerable narrative gifts. From Josie’s eyes we see her children — gorgeous and feral, enjoying this trip so much her main task becomes to avoid casting the shadow of adult worry on their activities.

Eggers beautifully evokes a mother’s pride. From Josie’s eyes we see her delight in Paul, for the stoic care with which he takes care of his sister, and Ana, for the abandon with which she tackles the world. “That she could enter any room, any bathroom, in Homer, and know the object most likely to be broken, and just how to go about it,’’ gives Josie a swelling confidence that in a battle versus the world, it is her daughter who would win.

To anyone who has crammed into a car with parents for days on end, “Heroes of the Frontier’’ will send a gust of nostalgia up time’s chimney. This is and isn’t the point. The book soars as an adventure tale, yes. It feels like driving deep into Alaska.

It also feels like life, as Lorrie Moore put it in one of her story collections: How even in its best of times, reality is provisional and strange, and the search for stasis is a fool’s errand. “Heroes of the Frontier’’ reminds us that this uncertainty principle applies to parenting too, and pays tribute to the capacity for children to weather change.

Heroes of the Frontier

By Dave Eggers

Knopf, 385 pp., $28.95

John Freeman is the editor of the literary biannual, Freeman’s, the latest issue of which is themed to family.