|No cover image, but this is a good representation|
I've already talked quite a bit about my thing for L. M. Boston and our visit to her home during our UK trip, so let's consider that part as read (follow links for info!) and get right to the bit where I got a copy of one of Boston's lesser-known works through ILL. Strongholds is a novel for adults and was published in 1969. It has also appeared under the title Persephone--that's the protagonist's name, though she usually goes by Persie or Zephy.
The short version: this would make a great selection for Persephone Books to publish. I think they should, and I emailed them to suggest it, though obviously it will never happen. But it should! It's a lovely novel, kind of odd, and it's just about been forgotten.
Persie is a country girl, illegitimate and quite poor, and at fifteen she is perfectly happy as long as she can be outside and work on the local farm. A horrifying (to her) incident precipitates her sudden departure, and she fetches up, shocked and ill, on a doctor's doorstep. From there she travels an odd road to maturity, finding strongholds along the way until she reaches an unexpected home.
It's a romance, but I don't mean either that it's a love story or a Gothic novel. There are elements of both, plus a large dose of Bostonian unexpectedness. I don't know of a lot of authors that would put a character into a perfectly realistic convent or mental hospital.