Dave McGillivray could write a book about his 3,452-mile journey from Medford, Oregon, to Medford, Massachusetts.

At age 23, he ran across the country, averaging more than 40 miles per day over 80 days.

Estimates are that he raised about $100,000 for the Jimmy Fund along the way. But it was 1978 and without a laptop (invented in 1981), the Internet (invented in 1991) or a GoFundMe page (invented in 2010), following the course and counting his donations involved a fair amount of guesswork.

It was payphones, AAA maps and two buddies in a mobile home.

“Honestly, we could’ve raised $150,000. Who knows?” said McGillivray. “Cash and checks were coming in from everywhere along the way, some were mailed in. We just sort of wung it.”

For McGillivray, who’d hatched the plan while a student at Merrimack College, those 80 days changed his life, changed his goals and changed his path. There were many tearful stories along the way.

But that last day, when he arrived in his hometown of Medford for an incredible ceremony before several thousand onlookers, then ran the seven miles to Fenway Park for another ceremony before a sold-out Red Sox game, may have taken the cake.

McGillivray said he woke up that day feeling good. He’d decided to accomplish the run in 80 days. It was the 80th day.

“It was the first morning I got to sleep a little longer, getting up at 7 a.m. rather than the typical 5:30 a.m.,” he said.

One issue was that he and his crew had miscalculated the distance of the overall course by 250 miles (because of those AAA maps).

So, that last day, he was about 25 miles to Medford.

“I only had to run a marathon that last day,” he joked. “I wound my way through Newton, Watertown, Somerville and then, finally Medford, where people were on the city line cheering as I got there.”

The Medford High School cross country team was there wearing T-shirts that said, “Dave’s Escorting Team.”

When he got to the Mystic Health Club — where he’d worked out almost daily leading up to the cross-country run — he was forced to stop for a brief ceremony to receive a trophy bigger than he was.

“That was special,” he said. “... I had been working out with so many people at the club, it was like home to me.”

McGillivray then ran to Medford City Hall, where the mayor and a few thousand others were waiting. Among them was Bill Rodgers, at the time the best marathoner in the world — he’d won Boston four months earlier.

“It was very emotional for me,” said McGillivray. “I mean, Bill Rodgers was at the height of his popularity. The place was mobbed, jammed with people. My parents and family were there, and that ceremony was special.”

But that was only the first part of the final day. The other was happening a few hours later, at Fenway Park, with McGillivray planning to run to the park and around the confines.

As he was about to start for Fenway, the motor home that had traveled every mile with him would not start.

“It literally broke down,” he said. “The ironic thing was the human outlasted the machine. What a fitting conclusion.”

McGillivray left the motor home to be towed and took off for the last leg of the tour.

About 90 minutes later, he arrived at Fenway and was met by Red Sox TV play by play broadcaster Ken Coleman, who also was a chief fundraiser for the Jimmy Fund.

“They brought me in the area where all the lawn mowers, peat moss and grass stuff was,” he said. “I met up with Ken Coleman about 10 minutes before the game, standing at the garage door down the left field line. I remembered looking out, not sure how many people would be there before the game. It was jammed. It made me a little nervous.”

The plan was for McGillivray to run around the park, counter-clockwise, around the warning track toward the bullpen, then down the right field line toward home plate.

“I started running, the fans were so loud, I couldn’t hear myself think,” he said. “It was incredible. As I ran by the bullpens and down the left field line, it got louder. I got to the Red Sox dugout and I see all of their stars — Don Zimmer, Jim Rice, Bill Campbell, Dennis Eckersley, Bill Lee, Dwight Evans and Jerry Remy all on the top step cheering.

“Bill Campbell threw me his hat as I ran by, and I put it on, and the fans went crazy,” said McGillivray. “I was supposed to stop at home plate, but I just kept going and did another lap. John Kiley, the organist, kept banging the keys away.”

McGillivray finally did stop at home plate the second time around. He gave Coleman an empty envelope — a gesture representing the $100,000 that the Jimmy Fund had received during his run.

He later went up to the booth and chatted with Coleman about the 80-day experience.

“I saw Bill Lee after the game and he asked me, ‘Wow, that was amazing. You ran through the desert and Rocky Mountains?’ I said, ‘Yeah.’ In classic Bill Lee fashion, he asked, ‘Did you see God?’”

Last, but not least for McGillivray, were kids holding baseballs, asking for his autograph.

“I was stunned. Me? It sort of hit me there, while I was signing some baseballs, that this was a game-changer in my life. It probably would change the path in my life. As I look back on it, I organized it myself, taking four years to plan it.

“I’ve done a few things since then,” said McGillivray, downplaying a few dozen accomplishments like his “seven marathons in seven months in seven continents” last January and February.

“But that run across the country 40 years ago was the highlight of my athletic career,” he said. “I said then — that’s how I want to live the rest of my life. I think I have.”