I could do the island thing as long as I could be sure my sisters & the pets were taken care of while I was gone.
For the money, I see a problem: How do you keep this a secret from the IRS? And how can you keep the spending secret when the stuff you buy is going to become obvious?
But assuming those 2 problems are resolved, I would pay off my house, buy an old Victorian house in a neighborhood more in keeping with my interests, and have it remodeled and furnished to my tastes (sticking to the vintage theme though). I would probably spend the bulk of the money on investments that would guarantee me an income so I could quit my job. Anything not spend on me would be spent on certain charities and on my sisters.
I'm going to Hell in a handbasket. Well, at least I'll have a view. Oh, I will see the fire, through the rusty razor wire. Oh, don't you worry, I saved a seat for you. (Voltaire)