Mount Thielsen looms behind Eugene author Bob Welch in 2011.

They say a journey of a thousand miles begins with a single step.

For Oregon author and journalist Bob Welch, a journey of 2,650 miles began on the 455-mile Oregon stretch of the Pacific Crest Trail in 2011.

Initially, Welch and his hiking partner, brother-in-law Glenn Petersen — or “The Oregon Boys,” as an Australian hiker on the Pacific Crest Trail dubbed them — didn’t set out to do the entire trail, which runs through the Sierra Nevada and Cascades ranges in California, Oregon and Washington between the border of Mexico to Canada.

“And that was all we were going to do,” Welch, 69, said of their Oregon run. But in 2014, Petersen suggested they tackle the nearly 200-mile John Muir Trail in the Sierras, which runs in conjunction with the PCT and passes through Yosemite and Sequoia national parks.

“I was kind of ready to be done, but the idea of going down to the High Sierra was alluring,” Welch said. “Once we got that done … we thought, ‘Wow, we’re almost a third of the way done. Why don’t we just go for the whole thing?”

Well, for starters, they were decades older than the 20- and 30-somethings that predominate on the trail; Welch was 68 when they completed their last section. And rather than start at the border of Mexico in the spring and advance toward Canada with the thaw, doing the length of it in one fell swoop, Welch and Petersen tackled their feat in sections over a decade, skipping around geographically and directionally.

“We hopscotched all over the West Coast, going north-south,” he said. “Maybe at the start of the summer, we’d be in California going south, and at the end of the summer we’d do two weeks going north in northern Washington.”

Welch and Petersen, who are married to sisters Sally and Ann, respectively, first hiked the trail’s Oregon section in 2011, an experience Welch wrote of in 2012’s “Cascade Summer.”

“When we committed to doing the whole thing, I have an email that says, ‘Hey, I think we can do this thing in seven summers, and when it’s done, that’s what I’m going to name the book.”

They did, and he did. Welch will visit Paulina Springs Books in Sisters on Thursday to promote his latest book, “Seven Summers (And a Few Bummers): My Adventure Hiking the 2,650-mile PCT.”

Welch, a longtime columnist with the Eugene Register-Guard before stepping away in 2013, is still actively writing books, and Petersen is a full-time medical doctor. Welch and Petersen completed their journey, which required hiking 17.9 miles a day over a sum of 148 days, but it was not without challenges — the “bummers” of the subtitle allude to things happening off-trail as well, including ailing parents, COVID-19 and fires.

“You gotta balance your life with the trail, whereas the young ones who start in late March and April from Mexico and just go straight to Canada, in some ways they have an advantage in that it’s simpler for them. It’s like, ‘OK, I’m devoting five months to hiking this trail. That’s all I’m gonna do.’”

Doing it as a through-hiker gives one the advantage of getting in increasingly better trail shape as the journey progresses, Welch said.

“By the time they are to Oregon, they are lean and mean,” Welch said. By contrast, The Oregon Boys were doing it on again, off again.

“We pieced together 17 sections over 11 summers,” Welch said. “There’s all the logistics. I think we figured out that we traveled about 17,000 miles to get to and from trailheads over the years.”

For logistical help, wives Ann and Sally were “the wind beneath our wings,” Welch said. “They did a lot of driving up and down the West Coast getting us to and from the trailheads.”

Welch said that his and Petersen’s different polar-opposite personalities complemented each other during their journey.

“He’s very calm, methodical, patient, whereas I am very impetuous, impatient and spontaneous,” Welch said, laughing. “I think we worked well together as a team. At least I think we did.”

What: Bob Welch discusses “Seven Summers (And a Few Bummers): My Adventure Hiking the 2,650-mile PCT”

When: 6:30 p.m. Thursday, Oct. 5

Where: Paulina Springs Books, 252 W. Hood Ave., Sisters

Cost: Free

Contact: paulinaspringsbooks.com, bobwelchwriter.com