There's no sizable pro-free trade bloc in the Florida electorate. Not sure what demographic you're suggesting exists that would vote like that. In a lot of Rust Belt states, it's easy to point out which folks are voting against free trade, because the impacts of free trade are tangible (this factory shut down, that kinda thing). There's no opposite effect of similar magnitude in Florida, or anywhere else for that matter.
Yeah, the benefits of trade are diffuse, and I don't think there's really any sizeable "pro-free trade" voting bloc anywhere in the country.
I'm still curious as to how the issue will play out in 2020, should Trump actually be a protectionist president. If he's not making trade deals, then there won't be any TPP equivalent for other candidates to either oppose or support. If the president himself is protectionist, then such deals simply don't get negotiated in the first place, so there's nothing to talk about. Though I suppose you could have a situation where Trump gets us into a bunch of trade wars, and that creates a rallying point for some. But if he simply stops negotiating new trade deals, then how does the trade issue play out?