It sounds a lot like the Long Island NY area and a lot of other places across the country.I'm a little familiar with the area having traveled there a few times.

I highly agree with @Ray Hage I lived and purchased properties in both places lived in Suffolk Long Island and currently reside in Tampa Bay by far the best return is in FL.  

The area near Hutchinson island looks like it's getting rapidly developed.

TitleEase is a company with a great team out of Rhode Island that I got to know personally.

@Manuel Toledo check out local credit unions like SDCCU and North Island Credit Union.

Retire on an island?

I bought my 2 barrier island Florida STRs from tired landlords, who carried back a mortgage for me at 6% interest only.  

@Solomon MorrisYes.

Granted there are more factors at play but distilled down you can't increase the land supply on Hilton Head as we are an island, and the demand for location on the island remains extremely competitive.

Then there are local ordinances that require park benches and raised islands with trees and shrubs, sidewalks and other beautification requirements.