"They've been excellent," Holloway told the club's official website. "This will help them get to know people, eating together, training together, staying together.
"It's only been five or six days, but that's been important for me - that camaraderie and getting some decent training under their belt.
"People like Jerome and Gayley typify what Palace are all about really, with young people and hungry people. Hopefully our fans will get to love them and sing songs about them."
Holloway's men begin their Premier League campaign at home to Tottenham Hotspur on August 18.