I would stop by any restaurant, coffee shop or Hotel parking lot. Most have free wifi and you usually can pick up their signal without going in. You might even find an unsecured signal at the house in chicago.
If you are looking for a cell based option you can tether or buy a broadband card. To legally Tether you are supposed to use Verizon's $50 a month data package, although, if you have their $29 plan you can hack your phone to share with a laptop, but you are violating your user agreement.
Another option is to use a prepaid celluar card from Virgin. I have a client that was pretty happy with it. Plan can be $10 for 10 days or $50 for the month and it is pay as you go.
Check out their site for more info
http://www.virginmobileusa.com/mobile-broadband/
