I too have been researching cooling my 1 car garage workshop.
For my purposes (hobbyist plus car in garage when tools not in use) I am almost decided on the portable AC units.
My understanding is that swamp coolers (evaporative cooling) won't work in Florida.
Has anyone used the portable AC units? They have small intake and exhaust hoses about 5 feet long. I plan on opening the garage door a few inches and putting the hoses there when the AC is in use. I'll put some scrap wood along the rest of the door to seal it a bit.
The portable units are very expensive compared to a window unit about 5-600 $ for 10,000 BTUs. I'd like to get the temperature down to about 80 within 45 minutes.