This book was something out of character for me when I was a kid, but I also loved history, so I gave it a go. I think it could be a full-length adult novel, with just a bit more embellishment. It tells the story of Kate, a girl who moves into a historic house for the summer, which her parents are renovating, which ends up being the house of a distant ancestor, Patrick. To Kate's shock, she wakes to find that she's gone back in time, to 1850, where she lives with her widowed mother and several brothers and sisters, all mill workers struggling to survive. Predictably, Kate falls in love (or at least becomes smitten) with her "relative" Patrick, who is caught up in local strife between anti-Irish town residents and worker's rights activists at the mill.
The book is a good introduction to what life was like for poor immigrants at that time, making young adults more eager to learn about this period of New England's history. The story is well-told, enhanced by a fair amount of detail regarding the daily life and struggles of what were definitively second-class citizens at the time, which resonates even today.