Saftey smafety...
Stay downtown. Downtown Chicago is a the greatest city in the world in the summer time. Hyatt and Sheraton have very nice hotels right on Michigan and the chicago River. Tons of things to do. The Loop is very safe. A $5 cab ride to Navy Pier. Go there in daylite hours if you have a small child--but the ferris wheel at night is ver cool. Take small tour boat (docked on the river near Sheraton and Hyatt). One is an historical tour on the river, and another takes you out on the lake. The skyline is awesome on a clear day or clear night.
Other free stuff?
Millinium Park (south loop but north of soldier field) $500 million public park/ amphitheater
opened in 2003?
Hampton Suites (illinois and Dearborn St) is another hotel that is clean and affordable. The Cubs free agents and rookies live there during their first season. Very close to Michigan Ave, Weber Grille, House of BLues, Harry Carays. My friend was a manager there for years . I used to see Kerry Wood, Zambrana, and others there as rookies.
Don't stay in a suburb or O'Hare to save a few bucks. A complete waste of time out there unless you're flying out somewhere the next a.m.