As a Californian, I always had the impression that Florida was a more humid version of California. When I moved to Florida last year, it was to Miami, and I had a culture shock at the incredible urbanization that had occurred in the heart of Miami. I was lost in the city, finding it more confusing than L.A. I also enjoyed getting to put my Spanish minor to use! Coming to Orlando, it was a clean, tourist area, more like what I had envisioned. I do not think that it appears to be part of the South.
But as the reading says, there are many rural areas of Florida left, and dense forests and swamps leave some regions mostly unpopulated. I accept the argument that Florida was part of the South as of the 1800s, but today, it is its own area, detached from the South on three sides, and would be described as tropical before it would be described as Southern.
Florida benefited from WWII as the rest of the South did, but with the increase in population, the influx of Latin Americans and other tourists, Florida no longer can be identified as a Southern state.