Luggage and bags:
In this day and age, any air traveler should carry several one-quart Ziploc bags with them, to be used for the 3 ounce (or less) carry-on items -- lipstick, suntan lotion, deodorant, toothpaste, etc. -- which must otherwise be discarded at airline security screening.
Clothing/Shoes/Weather Gear: Summer: Sandals and tennis shoes. (Many yacht charter services prefer that you wear Tevas or other appropriate nautical shoes.) It can get quite hot and humid though less so at the shore, so plan accordingly. Winter: Boots are not always required, as snowfall has been sporadic in recent years, but warm coats, mittens, scarf and hat are necessary.
Toiletries and Medical Supplies: All readily available, although travelers from overseas should have adequate supplies of their medications, some of which may not be FDA-authorized for sale in the USA. Some items available over the counter in Europe are only available by prescription in the States.
Photo Equipment: All readily available.
Camping/Beach/Outdoor Gear: Whatever you'd use at home will likely be helpful here, but can easily be purchased if you forget something.
Miscellaneous: Although the climate isn't especially rainy, I find a small umbrella to be useful.
In the summer, shorts and your bathing suit. This isn't called 'The Ocean State' for nothing! In the fall, well...sometimes you need just a sweater, sometimes short sleeves, other times you'll need a parka...come to think of it, that goes for spring, too! Winter means layers, lots of em!
Toiletries and Medical Supplies: This isn't Siberia, you can find everything you need, so don't worry!
Pack some good walking shoes. You'll explore the homes and paths, up and down hills near downtown.