You can camp on the island if you choose or stay at a B&B for a minimum of $400 a night up to $800. We only went over for the day, but maybe some time later we might go over to camp. There are no paved roads, stores, or other conveniences. Don't think we'll ever stay at the B&B.
That hike was around 3.5. That was no problem except crossing the sand dunes heading back was tough. It was hot and the white sand was like a heater exploding the suns rays all over us. Whew! We made it.
I don't know what the ruins are all about. We saw wild horses and turkeys. There are some 150 horses that roam freely all over the island of about 17 miles around.
The wind wasn't blowing much so we didn't do much sailing. Maybe next trip we can do that.