I used to read a lot of these books. Don't know why I stopped. To me this is Travis McGee...
In 1983 a TV movie was made of the novel, The Empty Copper Sea.
Sam Elliott! yum...
I read The Dreadful Lemon Sky for the Color Coded Reading Challenge. I read it for the category 3. A book with "Yellow" or any shade of Yellow (Gold, Lemon, Maize, etc.) in the title.
The Story: Travis has a visit from an old friend, Carrie Milligan, who gives him a pile of money to keep safe for her. If she doesn't come back for it in 2 weeks, he's to give it to her sister. Carrie dies. It's supposed to be an accident. Travis and Meyer head down to Florida to find out what has happened.
Here's a nice article about John D. MacDonald and his work from the Washington Post. Mr. MacDonald wrote a lot for movies and TV. Apparently, Leo DiCaprio is in development on a Travis McGee movie.