I flew the route this week. First, it is only one flight. The ORD flight stops at SFO for an equipment change. Second, I was out of customs/immigration at about 7 p.m. even with no checked baggage. Third, the other airport is a LOOONG way away. I would not attempt without a local driver waiting to whisk me there and then hope the traffic is light. I would schedule a minimum of 3-4 hours. Better to get a nice hotel room and see the city for a day. It is very impressive.