yes, long island city is in queens, which is on long island
Fire Island is part of Long Island. It woudl be more helpful to ask how long it takes to get to Fire Island from a particular Long Island town.
Partially, There is always a water boundary line between states
Long Island, with an area of about 1,400 square miles, is larger than Rhode Island, which takes up about 1,040 square miles.
4-6 hours give or take and if you go by ferry usually 4 driving it took me 5 hrs once