I hear ya. Also live in South Florida, two blocks off the beach. In my case, single family home with an enclosed garage, so not as big a deal as you.
Your big concern is not so much sand, but salt, salt air! This is seriously corrosive. I can tell you from experience that you'll see corrosion in places you'd never expect it. Keep the windows and sunroof closed when parked and sitting. Also, make sure your tire air valve caps are always there. If they disappear buy a dozen spare caps and keep replacing them. Seriously. The salt air will corrode the valves and TPM sensors over time.
As far as sand on your paint. Is there construction going on in the area, or do you think this is beach sand? If no construction, its likely a combo of beach sand and salt. Wash and wax the car often.
A car cover can help. For South FL I prefer the Evolution fabric covers from Covercraft. IMO, the Evolution fabric is the best all around solution for South FL. If your car has light sand on it, the fabric backing should protect the paint from scratching. If sand is heavy and its windy outside, then I'd be careful.
That's my 2 Cents.
P.S. I have a Covercraft Evolution E90 sedan cover if you're interested in checking it out. PM me.