On page 75 it says that the kids are trying to sell Al Capone doing their laundry. There has been no record of kids selling Al Capone doing their laundry.
Throughout the book the text states that Moose took the ferry to the bay every day. According www.insideedition.com to kids actually did take the ferry to school but they sometimes went with their parents if they were younger kids. For very young kids there was a preschool on the island.
Throughout the book the text hints that the guards families lived on alcatraz. The families actually did live on alcatraz.
On page 221 it says that the convicts played baseball . According to www.nps.gov the convicts talked about baseball but they actually played softball.
On page 135 Scout asked Moose for a ball. There has been no record of other kids trying to get a ball from alcatraz.
On page 53-57 it says that the kids had fun at the parade grounds. That was also like their meeting place. According to www.insideedition.com kids actually did play on the parade grounds.