The miles, Matt Gregory walked them for her. All 5,000 of them: from the lush green of Bellingham, along the coasts of Oregon and California, through the dry heat of Arizona and Texas, and then down the humid coastline of Florida.

It was the memory of his mother, who died in 1999 after battling a second cancer, that kept him going day after day since leaving his home on Sept. 1, 2006. That, and his desire to raise money for the Fred Hutchinson Cancer Research Center in Seattle, which he credits with helping her to live another 20 years in her first goround with cancer.

On Thursday, the 28-year-old Bellingham resident’s coast-to-coast trek ended in Key West, the southernmost city in the continental U.S., with a fully clothed, celebratory jump into the waters of the Straits of Florida.

“I was pretty emotional. It’s still sinking in. I’m done, it’s kind of weird,” he says soon after walking the last 17 miles of his odyssey.

In the days leading up to the end — it included tears, screams of excitement and sprays of champagne — Gregory talked about his walk, the people he met along the way, and the next steps he’ll take.

An idea, “a leap of faith”: The inspiration for a cross-country trek came from his best friend.

“For some reason, this idea was so appealing, something about the adventure of it,” says Gregory, saying he liked the thought of traveling from one place to another without knowing what was going to happen.

But, then, his friend backed out. Gregory decided to do it anyway. He quit his job at Sound Beverage, sold his truck and set out. It was 30 days from the germination of the idea to his leaving.

“It’s a leap of faith. It happened so quick and I went for it.”

Soon after starting, Gregory decided that he wanted the walk to be more than an adventure. He wanted a purpose. He wanted a way to help others. He wanted to do something to honor his mom, who had died in 1999 while battling melanoma.

“My mom was the most important person in my life,” says Gregory of the woman who was one of 18 siblings. “She channeled a lot of love into me.” The melanoma was her second bout with cancer; her first was with leukemia when she was pregnant with Gregory. He was born prematurely as a result. She received a bone marrow transplant at Fred Hutchinson Cancer Research Center in 1979 — giving her another two decades of life.

So he set out to raise money for cancer research for the center.

“We think it’s wonderful,” says Christi Ball Loso, spokeswoman for Fred Hutchinson Cancer Research Center.

“It’s raised funds, which is terrific. It’s raised awareness about what the Hutchinson Center does,” she says, adding that Gregory’s walk also has raised awareness about the need for cancer research.

His mother was 43 years old when she died. Gregory was 20. He rushed from Oregon, where he was going to college, to Elma in Washington to say goodbye. He was surprised by the disease’s turn.

“She looked like she had it beat,” he recalls. “She was a real strong woman, the type of person … she’d rather keep things to herself than make everyone worry about her.”

With a little help … Gregory wants to raise $100,000 for cancer research. He’s raised $11,000 so far.

He’s undaunted by the money still to be raised, saying he hopes proceeds from a book he plans to write and the documentary he plans to make of his walk will help him reach his goal.

Maybe he still has faith because he’s received so much help along the way, from local businesses like REI, Superfeet and Fairhaven Runners & Walkers. Like other merchants, these locals gave him big discounts on the supplies he would need or advice on how to navigate his journey. He also received two free backpacks from Gregory Backpacks (no relation).

The generosity is something that has followed him across the country — from hotel managers who donated rooms for him to stay in when he wasn’t camping, to those people who opened their wallets and gave him money for his fundraising efforts, to strangers who didn’t know him but still invited him into their homes for a night or a meal.

Gregory says he’s stayed in at least 109 homes, most of them strangers to him at first.

“It’s been amazing,” he says. “People are generous in the United States, I’ve found.”

Planning his route: Gregory had just a rough idea of the path he would take to cross the country. The first day, he knew he wanted to walk nine miles down Chuckanut Drive, where he would meet up with two friends to camp. The next day he walked to Anacortes. As he went, he relied on the people he met along the way to provide information on the best routes or areas to avoid to stay out of danger.

“There are so many days where I don’t know where I’m going. I get up and walk,” says Gregory during an interview on the 431st day of his journey. “Much of the trip, things fell in place and worked out.”

Walking in his shoes: Gregory is on his ninth pair of running shoes. He’s also on his second backpack, which weighs 45 pounds when filled with necessities such as a change of clothing, a tent, trekking poles, digital camera, water bladders, rain poncho, toiletry, digital camera, a stove and cook set.

The longest distance he walked in one day was 35 miles. There were plenty of days he walked 20 to 28 miles. But the journey slowed dramatically when he hit stifling heat and humidity in the southern U.S. “It’s hard to want to walk outside, much less with a backpack on,” Gregory says.

That was especially true in Florida. It took him 300 days to walk to Florida, and another 134 days to travel through the state to the completion of his journey.

Hardest part of the journey: He’s met many people and he’s been interviewed by at least 70 newspapers, 37 TV stations and 12 radio stations in his fundraising efforts. But he still got lonely, especially in empty stretches like the Sonoran Desert of southern Arizona.

“You get used to loneliness but it’s still difficult.”

The beauty he’s seen along the way: Gregory says he was struck by the tall redwoods he saw along the coast of Northern California and the stately, tall cacti with arms in the Sonoran Desert. “The desert had its own beauty. It was cool seeing those cacti.”

He also loved the bluebonnet wildflowers he saw near Austin, Texas. “It’s like a sea of blue on the side of the road.”

The next steps: After took his last steps on Thursday, his plans are to return to Bellingham via train, which will take him up and over the top half of the country so that he’ll have made one giant loop of the U.S.

People have offered to buy him a ticket. He’ll need the help. The journey cost him about $5,000, and he comes back to no job and no savings.

But his outlook remains optimistic, as it has during his journey.

It had to be, he says, to keep him going — one step, then the next, for all of 5,000 miles.