I've finished writing book four of the Hall of Doors series. It's tentatively called The Secret Door. In this one, Sammy and her mother are going to move away from the house where Sammy has lived most of her life, away from the place from which she (with the help of the cats) has been able to "climb a moonbeam" to Princess Selena's castle. Naturally, she's upset. But Peaches the cat takes her up the moonbeam path for another adventure.
I won't give you all the details, but the story includes unicorns, as requested by granddaughter Maggie. It also includes the "wild and dangerous teddy bears" she wanted, except that these are more like bandit koalas. I did have to pass on the space aliens--I couldn't see any way to work them in:) There are some tense moments, but Sammy makes it safely home again with the possibility that she may be able to return.
For a brief synopsis of the first three books of the series, see my website at www.janiceclark.net