Children's ghost story/mystery/time travel, 60s-70s

Set in Britain, I think (not positive), in a house that used to be an inn. Both ghosts and time-travel, some kind of mystery associated with the house. The children had either just moved there or were staying there with relatives.

I remember a scene where the children (there were two or three, I believe) sign in at the past inn's register, their plain modern-day signatures looking very out-of-place among all the elaborately flourished other signatures.

I would have read this in the 80s, probably, and it didn't seem like a new book then.

one of The Magician's House Quartet?
The Steps up the Chimney

No, that's much too recent. Thanks anyway.

I can't remember the title but there is a book like this about a girl named Nine Taneleven who stayed in the inn that her father was renovating. There were ghosts and she had her best friend with her. It may have been by Bruce Coville

The book I was thinking of is The Ghost Wore Gray by Bruce Coville. There are two girls who are staying at the inn while Nine Tanleven's father fixes it up. I just started reading it again and don't know if it fits your description or not.

ETA finished and it sort of fits. set in New York State but does have a mystery and ghost and sort of time travel. I didn't see the scene you described but do remember that signing from somewhere.

Found:

Andre Norton's Red Hart Magic.