Although we'd like to think this thing drifted from somewhere else in the Caribbean,
Occam's Razor would suggest it was more likely lost in the Keys not far from where it was found. However, the OP didn't think any of the photos looked like the Keys.
The tanks in the truck bed are doubles with wings, and that might be a DIN first stage on one of them. Assuming they're rentals, this suggests maybe deco or cave diving, which limits the number of places and suppliers. Mexico again pops to mind for it's cave diving. If it's the Mayan Riviera, some of those resorts have pretty oddball combinations of architecture.
In the beach photo, there's a pay phone in the background, with a white phone image on blue background, on the sides. Looks sort of American in style, although the firehose box on the end of the residential building looks less so.
The truck looks like it's maybe a left hand drive.
*stage.com implies the area may be English-speaking.