One house, two families, years apart, bit of a mystery?

I read this book when I was younger, around the mid 2000s. I think it was a middle grade novel. It was about two children, one from one place in American history where there was conflict (Civil War?) Who wrote everything down in a diary of some sort, particularly I remember that in the older time period, a visitor came and had to be helped by the family. The one in more modern times (whenever that is) I think finds the diary and starts getting into learning about the other child. I never finished. I don't know if there's time travel or anything but I feel it may have been leading up to it. I think the modern person could hear the voices of the older people in the house? As if they we in the same room in the same time. Does this ring a bell to anyone?

The details don't match exactly, but it reminds me of The Court of the Stone Children - in the more modern times in San Francisco, the girl finds a museum with objects from a chateau and can interact with the spirit of a young woman who lived there during the French Revolution. There is also a diary that she finds and reads to help her solve a bit of a mystery.

Some overlap with Louise Marley's The Glass Harmonica, but it's a long shot.

>2 Caramellunacy: Hi! Thank you for your reply, but unfortunately that's not the book. Thank you for trying!

>3 beyondthefourthwall: Hi! No, that's not the one, but thank you so much for trying.

I also thought of Annie Barrows's The Magic Half, especially as the sequel is Civil-War-related, but those are probably a little too new.