Hey Gerry....I like to travel light myself, so any warmer clothes I may need, I wear on the plane...jeans, walking shoes, socks, hoodie etc. Carry your laptop as your personal item.
In your carry on suitcase, towel, snorkel, mask, ( I would pass on bringing the fins, they take up too much room and aren't really a necessity imo) bathing suits and some shirts. Put your camera inside your fanny pack, make use of every inch. Roll your clothes. Anything else you can get there. Have a great time.