The Last Word by Taylor Adams

 Emma Carpenter is house sitting on the coast of Washington. It's an old beach home and the only companionship she has is her dog Laika and the next door neighbor. The communication with the neighbor is done via a white board. It's the off season and Emma is essentially isolated. 

She spends her time reading books but after reading a terrible horror book and posting a negative review she finds herself at the mercy of the author. They engaged in a exchange of words and then ... Emma finds herself as a character in her very own horror novel. 

This book is better than most cat and mouse troupes. It's intense and action packed.