Andre Norton 
Octagon Magic 

An orphan girl meets the inhabitants of the mysterious Octagon House—and discovers a portal to America’s past—from the Gandalf Grand Master of Fantasy. Lorrie happens upon a strange and fascinating secret! Did a witch live in the eight-sided house? Was it haunted? There were lots of scary stories about the strange house—but none could match the secret Lorrie uncovered. One day, she climbed the high iron gate and escaped into the garden to save a kitten from some cruel boys—and met the mysterious lady of the house. The woman let Lorrie explore all the odd-shaped rooms. In one of them was a rocking horse and a large, eight-sided dollhouse—an exact miniature of the big house. The dollhouse was beautifully furnished—as if someone lived there! It drew Lorrie back into exciting adventures that she had to face with courage and daring!