I read a juvenile novel in the 1980s (from my school library). It may have been from the 1960s or 1970s about a very lonely girl who moved to a new house in the country, and while exploring, she found a secret playhouse that had dolls and teddy bears in it, and I think they came to life. Kind of like The Lonely Doll meets The Curious Clubhouse, but definitely not either of those! It had illustrations, maybe an orange cover, and I feel like Secret may have been in the title, and the author’s last name began with G or H?