Some guys of a certain age get fed up browsing the daily obituaries with a sense of creeping dread.

Their peers begin to pop up with alarming frequency in one “courageous battle with cancer” or “passed away peacefully” entry after another.

So finally they decide to stop daydreaming about a bucket list and leap headlong into the top item.

That’s more or less how Roger Netsch found himself on the eve of a 3,000-mile, cross-country bicycle ride.

“You just don’t know how long you have on Earth to do things like this,” Netsch said this week.

The 58-year-old Indianola schoolteacher was resolved enough to retire in December from his job of 33 years when denied a leave of absence for his odyssey.

Thursday, Netsch and five of his biking buddies, mostly retirees ages 50-63, will pile into a used conversion van that has logged 140,000 miles — not as many miles as they’ve collectively accumulated on bikes, to be sure. They’ll drive to San Diego, Calif., pulling a 12-foot cargo trailer stuffed with gear.

This so-called “Southern Tier Comfort Ride” crew (complete with matching “STCR” ballcaps) will pedal across the southern states, from California to St. Augustine, Fla., for more than 40 days on bikes.

Unlike the Register’s Annual Great Bicycle Ride Across Iowa, Netsch and company won’t have the benefit of a convenient pork chop or pie stand every few miles.

But, yes, these guys are the familiar type of two-wheel jockeys who swap war stories about, say, “Soggy Monday” on the ninth RAGBRAI way back in 1981. Bob German, a retired banker who lives in rural Dallas County, biked a northern cross-country route in 2001 and is so old-school that he boils his bike chain in wax in a Crock-Pot to lubricate it.

Netsch is a veteran of 32 RAGBRAIs who met his teammates through the Tall Dog Bike Club.

To train for this epic journey despite the sleet and snow, these guys have heaved weights, enrolled in spinning classes and ridden stationary bikes in their basements.

They’ve scrutinized potholes and the widths of bike lanes along their route with Google Earth.

They’ve been buoyed by the example of an even older “6 Over 60” team — bicyclists ages 64 to 68 from California — that in June plans to roll from Astoria, Ore., to Portsmouth, N.H., and raise money for the Wounded Warriors Project.

Netsch has incorporated charity into his own ride with a campaign to raise at least $11,500 for Mary’s Meals, the international organization that feeds hungry schoolkids.

STCR expects to spend $5,000 or more apiece to pay for everything from spare tires to the airline tickets necessary to swap van drivers along the route.

They will sightsee at the “leisurely” pace of about 12 miles per hour — even if their version of leisure includes a grueling 115-mile day across Texas with no fewer than 9,000 feet of climb.

On one hand, all of this helps these guys flee the creeping dread. But then again a ride on this scale, along unfamiliar terrain, zooms headlong into plenty of risk.

“We’re from Des Moines, Iowa, where Dr. Bob Breedlove lived,” German said. “So if you know biking here, you know what can happen to you and some of the better riders.”

Breedlove was the beloved orthopedic surgeon and renowned cyclist who was killed by a motorist in Colorado during the 2005 Race Across America.

Brian Myers didn’t think twice about it until he visited his grandkids in Iowa City last weekend and wrapped them in goodbye hugs.

“That’s when it hit me,” said Myers, a retired plumber from Dallas Center.

These Southern Tier riders had yet another reminder of mortality this week when four of them visited fellow bicyclist Michael Leo, a Tall Dog co-founder, in the hospital for surgery on a brain tumor.

So I met those four guys this week — minus teammates Allen Cohrs of Council Bluffs (the 50-year-old pup) and Phil Mattiussi of Adel.

One benefit of sharing so much road and so many cramped RAGBRAI tents for so long is that these guys are self-aware about precisely where their personalities diverge.

Myers is the unapologetic pack rat whose bike will be laden with rain gear, tools and a tiny bottle of Pacific Ocean water to be ceremonially poured out in Florida. (He might have mentioned something about a small flask of Southern Comfort, too.)

He’s also the resident chef with a list of recipes to be tested on the camping stove.

“When you’re retired, you get to watch Rachael Ray at 11 o’clock,” Myers shrugged.

At the other end of the bike-baggage spectrum there’s Ron Smith, 63, the elder and a retired speech pathologist.

“My motto is ‘carry no crap,’ ” he said.

The other thing about aging cyclists: Four out of these six riders have become recumbent bikes zealots, with Smith and Myers as the holdouts.

Netsch originally hails from the tiny northwest Iowa town of Terril, where he aspired to become a school band instructor until music “got to be more work than fun.”

Not so with his work study job at the University of Northern Iowa in Cedar Falls in which he taught disabled adults how to drive, including a 45-year-old woman with cerebral palsy. So for 15 years he was a special education teacher in Indianola, then in 1995 began working with at-risk students.

Netsch’s abrupt retirement — after his offer to pay for his own benefits during unpaid leave — became a topic of local debate. He’s “kind of at peace with it now” and plans to line up another job after the ride.

Indianola Superintendent Michael Teigland explained that granting Netsch his unpaid vacation could have set a precedent forcing the district to grant other teachers extra days off, regardless of seniority.

STCR embarks now in part to avoid the heat, but also because RAGBRAI, church mission trips and other calendar items fill the summer.

Netsch has joked with his pharmacist wife, Susan, that skydiving has lurked on his bucket list.

“But I think I might be pushing the envelope with her tolerance,” he confessed.

In all due diligence, I checked with Susan.

“Yeah, that’s not going to happen, I don’t think,” she said.

It’s a fine line between what makes you feel so alive that you stave off the creeping dread, and what just makes you likelier to end up in the obituaries sooner — whether we’re talking about defying the odds or defying your spouse.