Tl;dr version:
Gothic horror/romance
Creepy but not gory
Not historical fiction
Thanks, all!
ETA: Someone recommended Mary Stewart to me once, but i can never manage to get through her books, something in her style just bores me to tears. Also, similarauthors.com just told me to try Mary Higgins Clark, but i don't know about that! Is she in the spooky/romance genre?