Will and Michael Keane, Jesse Lingard, Sam Johnstone, Tyler Blackett and Reece James all travelled with the team on Friday, as well as new signings Luke Shaw and Ander Herrera.
Van Gaal insisted in his first press conference that every single one of United’s first-team squad will get the chance to prove themselves before he decides whether to bring in new signings.
And Herrera, a 24-year-old midfielder signed from Atletico Bilbao, told the club's website: “The tour will be a new experience for me.
"It will be my first time outside Europe. All the people have told me there are a lot of United fans in America and I can't wait to play in front of them.
"I am very happy and really enjoying being at the club and in the city. The first couple of weeks here have been great.
"Training has been good, similar to at Bilbao in that we train a lot with the ball. The coaches want us to have the ball and keep possession, which is great for the players.”James Wilson and Tom Lawrence, whom previous caretaker manager Ryan Giggs gave their debuts to at the end of last season, were not included in Van Gaal’s squad, nor Nick Powell.
And the futures of Patrice Evra and Bebe seem to lie away from Old Trafford after they were also left out of the tour.
Evra is reportedly close to a move to Juventus and Bebe could be moving to Benfica.
Wayne Rooney, David De Gea, Juan Mata, Chris Smalling, Phil Jones and Jonny Evans all travelled and will look to take leading roles in Van Gaal’s plans for the forthcoming season, while Tom Cleverley, Darren Fletcher, Ashley Young, Shinji Kagawa and Nani appear to have much to prove to remain at the club.
World Cup players Robin van Persie, Javier Hernandez, Marouane Fellaini and Adnan Januzaj have not travelled due to their extended leave following the tournament, while Michael Carrick and Anderson are injured.
Anderson's absence from the tour is due to a calf injury sustained in training. The Brazilian joined United in 2007 but has been an increasingly fringe figure at Old Trafford and spent the second half of last season on loan at Fiorentina.
United will play their first match of the tour against Los Angeles Galaxy next Thursday before taking on Roma, Inter Milan and Real Madrid in the International Champions Cup. Should they make the final, they will play a fifth match in Miami on August 4.