I've been to Miami a number of times and have also been on a cruise and visited Jamaica, although many years ago. Coupled with some research (gotta love map software and satellite images!), some of the places are real but many of the businesses exist only in my imagination.
One big inspiration for this novel was John D. MacDonald's "The Girl, The Gold Watch, and Everything." It's a favorite of mine for incorporating a puzzle to solve along with some humor. While I don't purport to match Mr. MacDonald's sharp wit, hopefully people will find Tracy's wry sarcasms humorous.
Time will tell.