I am searching for a book about monsters

I am trying to find the name of a book written in the 1960's by a writer of some acclaim about a New York publicist who decides to buy a Caribbean resort/hotel while on vacation, and the misadventures that follow.

I am searching for a book, not sure when it was written/ published, but my Mom read it in the 1970's or 80's. Also, not sure if it is fiction or non-fiction, but my Mom thinks that it was "...based on a true story..." It is about an American woman around colonial times, who was kidnapped by Native...

Hopefully someone has read this book and can remember the title and/or author. I know this is a long shot. The book is a very old book regarding the Russians who created an underground city which looked American. They placed couples in this city who could pass as Americans and had them raise...