70's would be a gift Ryan - although we had that last year, there have been other years with temps 20 degrees cooler than that and rain!! This ain't Florida!!! 
Shuttle from Midway is a good idea, and Midway is a much smaller airport than O'Hare. Chinatown is another story. We will actually be on the edge of it during one part of our cruise. But getting there from the hotel on Sunday might cost you a few bucks in cab fare, and then you have to get back to either Midway or the hotel from there, unless your Uncle can pick you up and do the driving.
Arrival in mid-afternoon on Friday is fairly common for those staying at the hotel. Chance to get boats inspected and prepped, and of course, the meet-n-greet Friday night in the bar.
