The Sherwood Ring

“But you’re talking - ” I gasped, “you’re talking as if you thought Rest-and-be-thankful actually is haunted.”
“Well,” said my father, “it actually is, you know.”
“But - ” I began again.
“Never mind arguing about it now,” my father interrupted me. “Wait till you see Rest-and-be-thankful; then you’ll understand. And take the look off your face! They’re not supposed to rattle chains or flap about wailing in misty sheets. All they do is come around sometimes when they happen to feel like it.”

A 1958 historical young adult novel with supernatural elements by Elizabeth Marie Pope.

When Peggy Grahame's father dies, she is sent to the old family home, Rest-and-be-thankful, in upstate New York to live with her cantankerous uncle Enos. Upon her arrival, she soon encounters an English university student, Pat Thorne, who's doing research on his family's history in the area... as well as Rest-and-be-thankful's resident ghosts, her Revolutionary War-era ancestors.

And the ghosts prove to be quite chatty. The four of them - Barbara Grahame, Richard Grahame, Eleanor Shipley, and Peaceable Drummond Sherwood - seek Peggy out over the course of several weeks to tell her each of their parts in the Grahame family's Revolution narrative. Their tale runs parallel to Peggy's own budding romance with Pat and helps her solve a little family mystery of her own.

Tropes used in The Sherwood Ring include:

Abduction Is Love: Kiiiiind of happens in a roundabout way; the abduction is accidental, polite, and kind of a rescue, and she quickly manages to get herself out of the situation. They do, however, fall in love.
The American Revolution: The setting of the narrative provided by the ghosts.
Color-Coded for Your Convenience: Dick - an officer in the Continental army - naturally wears blue, as does his love interest Eleanor; Peaceable - an officer in the British army - wears red, as does his love interest Barbara.
Damsel in Distress: Peaceable finds out very quickly that Barbara is anything but this.

"Will you mind very much if I run myself into serious difficulties now and again after we are married, just for the pleasure of seeing you rise to an occasion?"

Embarrassing First Name: Considering Peaceable's not the fondest of his own first name in the 18th century, it stands to reason that the embarrassment is compounded by the time we hit the contemporary sections and find that Pat Thorne has inherited the aforementioned first name.
Girl of My Dreams: after having a series of nitwits pushed on him by his uncle, Peaceable is rather disdainful towards women in general; he is somewhat startled to find that Barbara subverts all his expectations of her utterly.
Gorgeous Period Dress: Their 18th-century fashion gets in a few mentions from the ghosts; Peggy gets to wear one for the Independence Day Ball.
Gray Eyes: Barbara's pointedly referenced as having these, and certainly has the rational/stoic personality often associated.
Historical Domain Character: Washington gets in a few scenes with Dick.
My Sister Is Off-Limits: Surprisingly averted by Dick, despite the fact that he is clearly very fond of his sister and Peaceable is an enemy. He finds the whole affair amusing.
Officer and a Gentleman: Both Dick and Peaceable play this up, and despite the fact that they're on opposing sides of a very bloody war, they're extremely friendly and courteous to one another. Peaceable's treatment of Barbara, when she wanders into his hands, also exemplifies this trope.
Play-Along Prisoner: Peaceable makes a great show of how weak and pathetic and sad he is once he's thrown in Goshen jail... and then proceeds to escape the hell away from there the second his jailers finally decide he's not a threat and relax the terms of his imprisonment.
Plot Parallel: There are a few instances where Peggy's story echoes the one being told by her ancestors; occasionally she deliberately invokes it, like at the ball where she helps Pat avoid detection by using Peaceable's methods.
Poisoned Chalice Switcheroo: Barbara pulls one of these maneuvers against Peaceable in one of the most exciting scenes of the novel.
The Red Sonja: Peaceable is a rare male version. His response to Barbara's Poisoned Chalice Switcheroo-- done while he knows she's got sleeping drops on her, which she's made clear to him that she has-- is to propose marriage on the spot before passing out.
Right Under Their Noses: What to do when you're leading a guerrilla band of British loyalists in unfriendly territory? If you're Peaceable: camp out in the closed-up house of the man trying to catch you, of course. He pulls the same trick immediately after he breaks out of jail later on in the novel, heading straight for the house where all his enemies are gathered for a party and disguising himself as a waiter.
Secret Relationship: Barbara likes to think she and Peaceable have this going on, but, as Dick points out, neither of them are being particularly subtle about the fact that they're going to be married the minute the ink is dry on the peace treaty.
Snowed In: Enabling the aforementioned accidental abduction.
Story Within a Story: How the narrative is structured. Used extremely effectively.
Unresolved Sexual Tension: Dick and Eleanor clearly have this going on as soon as Dick returns and is quartered in her family home, mostly in the form of Belligerent Sexual Tension. They quickly get a Relationship Upgrade, and the UST switches over to Barbara and Peaceable.