The Thirteenth Floor by Sid Fleischman
After a strange message was left on their home answering machine, Buddy and his older sister Liz don’t expect a supernatural adventure into their family’s history. Unsuspecting that the other would follow through on the message, both of the siblings go to their grandfather’s old office building. There they find an unusual passageway on the hidden 13th floor. Where does it lead? Three hundred years in the past. Liz ends up in a barn shortly before it burns to the ground. Buddy ends up on a pirate ship. Once they are reunited, the two must find a way to save young Abigail Parsons from being hung as a witch.
A fast paced adventurous read with a bit of a history lesson thrown in for good measure.
Published originally in 1995, there are several references that date the book. I don’t know if many of today’s kids would be as interested as someone who was 12 years old in the early 90s.