That was Ryan Reynolds and Sandra Bullock's plan last weekend, as they explored Wyoming's Grand Teton National Park – with Reynolds, 34, carrying Bullock's son Louis in a hiking backpack, TMZ reports.
Bullock, 47, has a home in the Jackson Hole area, according to the report.
"It was a big group of friends," a source tells PEOPLE of the outing. "They've been buddies for over 10 years now."
The two actors are famously close, with Bullock surprising Reynolds earlier this month on the red carpet at the Los Angeles premiere of his movie The Change-Up.
"They are like family, like a brother and sister," another source tells PEOPLE of their friendship. "It's not a love affair. They've been friends for over 10 years, and they care for each other deeply. They support each other and have a lot of fun together."
Reporting by ALICIA DENNIS