After countless trips, where I usually get a car service and just chill after a long flight, given how increasingly bad traffic has become, even on a "good day," on my next trip, I may just take the subway. So, pretend I'm an idiot that has an unexpired Metro Card with maybe a dollar or two of fare left on it. When I arrive at JFK T-7, what specific steps must I take, from the fare to the trains, etc., to get to Chelsea (30th St between 6 and 7 Av.)? Also, is it likely I would be able to sit most of the way on a Saturday late afternoon? (If that's a no, the Subway will likely be a no.)