Casey Key today is a blend of past and present. Yes, modern mansions have sprung up along its shores. But those luxury residences are still accessed by a single, winding, narrow road, where cars often brush up against sea grapes and bougainvilleas, and sometimes one driver has to stop to let another pass.

There are no high-rise condominiums, grocery stores, fast-food joints, or traffic lights. In fact, commercial development is limited to a cluster of Old Florida motels plus an historic fish camp and new concessionaire at the barrier island’s southern end.