I think that that's good advice, my wife's aunt and uncle lived in Coral Gables, so we've spent quite a bit of time on the keys over the years: You travel an awful long way with no access or sight of the sea., in a car

I agree, but for some reason I'd say that it might be worth driving it once. October? Maybe not worst traffic season.

Other random Florida thoughts:

The Intracoastal Waterway (ICW) north of West Palm Beach and south of Biscayne Bay is quieter and more pristine than you might expect -- dolphins, osprey, all that.

Miami Beach is interesting. Less tacky than Vegas.

You need to get 2-3 Carl Hiassen novels for before/during the trip.

Clearwater, Gulf side is interesting, but not in any unique (IMO) way.

If heading south of Miami, brace yourself for ubiquitous, unavoidable Buffett cover bands. Reggae Buffett, Polka Buffett, Zydeco Buffett, Klezmer Buffett....

The population in the Keys resulted from somebody picking the US of A up, rotating it 45 degrees clockwise, and shaking it vigorously.

The Bahamas are reel, reel close to Florida. Think about that.