Catire Walker, 41, and his wife, Noel Zemborain, left their home in March with their four children.
So far they have travelled through South America and Central America in the van they have named Francisca.
Speaking in the Mail Online, Noel Zemborain, 39, said: "The essence of this is to make a family trip and, well, the festival gives a deeper purpose and a goal, but it's a family trip.
"Our trip is a lot like a trip of discovery."
She added: "We're staying in families' homes, we're meeting people in the different places we pass through, sharing with them and the Festival of Families has a bit of the same spirit."
The family have tracked their journey through an online blog.
The couple said strangers have repeatedly opened their doors to them, including in Mexico and said the only troubles they had included problems with the car and heavy rain.
To pay for the trip, they used their savings and raised money on a crowdfunding site.
Gustavo Martinez in Puebla, Mexico recently offered the family his home, he heard about their trip through a Catholic news service and reading their blog: "As a Catholic, I like to meet people in whom faith is something living, like a motor.
'When I saw the blog I thought it would be an enormous treasure to meet them.
"If I can provide a grain of sand to help them along the way, even better.'
Pope Francis is expected to be in Philadelphia for a short visit in September after touring New York city.