3/17 go to Leverick, rent a car and go to the Baths, much easier, you
get to tour the island
3/18 it's only about 2 hours, you will have plenty of time on Anegada
3/20 check your conditions at White Bay, it can be very uncomfortable, Great Harbor is always pretty calm.

As far as food, the pizza at Leverick is very good. Many places you can ask for the "bar menu" instead of the dinner menu. This way the you can get burgers and chicken wings. Anegada food is expensive, you have to order your entire meal by 4pm, and might be a good night to eat aboard.