"It's an emotional tie," says Barbara, who's 49 and lives in Flourtown. "It's spiritual."
For Charlie, the tie goes back to age 12, when he began to work on his friend Charlie Pfluger's family farm in Maple Shade. "I loved it right away," he recalls.
Charlie bought Paint, a young horse he wryly describes as "not overburdened with great speed," for $75 in 1943. The saddle was $5 more.
"I still have the receipt," Charlie says. "Paint was the first thing I ever owned."
The two began to ride competitively in South Jersey, where horses were still a common sight in the 1940s. "There were at least 10 people with horses in their backyards in Maple Shade," says Charlie, who remembers riding on back roads near the present site of the Cherry Hill Mall.
In those days regular rodeos were held at Maple Shade's "Totem Ranch," so called because of its two large totem poles. "Shirts vs. skins" basketball games - on horseback - were a favorite competition.
Charlie writes of riding "a very fast buckskin horse" during bulldogging competitions, which involve leaping from horse to bull and wrestling the latter to the ground. "I made some bucks with him," he recalls.
Despite all the fun, Charlie eventually got married and left farm work behind, moving to Northeast Philadelphia and working as a linotype operator at the Bulletin.
But his interest in horses never waned. And after Barbara started riding in 2005, he began joining her.
"We rode together every Monday morning for three years," says Barbara, describing her father as "a very good mentor" regarding all things equestrian.
Turned out Charlie was a compelling storyteller, as I can tell as he unspools one after another from his perch on the couch.
"I rode a bull down there at Cowtown [in Salem County, N.J.] once, but I started riding regularly at Totem Ranch," he says.
"They offered a $50 bill for anybody who could stay on him for eight seconds. People came from all over South Jersey.
"I stayed on for 61/2 seconds one time, and honest to God I thought, 'This is it.' I went right over on my head. And I think that was one of the better rides."
Barbara picks up their shared riding story, which began after she joined the Philadelphia Saddle Club.
Her father ended up being an ace instructor.
"He coached me for three years. I loved the freedom of riding the trails in the Wissahickon, and going out afterwards for a sandwich or a beer."
And then there were the stories.
"I'd say, 'Dad, you've got to write these down.' But he wouldn't. I knew it was important to keep some of these old details of this whole era that's been lost."
After she wrote an op-ed piece for The Inquirer about riding with her father, he came back from a vacation with a half-dozen spiral notebooks with his reminiscences. In longhand.
They finished the book in 2008; Barbara has since started a business recording and writing the reminiscences of others.
She still rides occasionally, while her father does so once a week.
"I never get tired of it," Charlie says. "I would ride every day if I could. I have arthritis in my back. But as long as the horse can run, I can ride."
Contact staff writer Kevin Riordan at 856-779-3845, email@example.com, or @inqkriordan on Twitter. Read the metro columnists' blog, "Blinq," at http://www.philly.com/blinq.