A week in Miami.

If it's anything like the five days I spent in San Francisco, just go to the raids and jump in the lobby. It will fill up quickly, even if you don't see anyone around.

I'm up in Tampa. Around here Discord is the way to meet/coordinate. It's actually huge. I imagine, though don't know for sure, that it's the same in Miami. Just create a Discord account and subscribe to the Pokemon Go raid rooms in the area you'll be in.