Good luck on finding family accommodations near downtown (unless you're a millionaire).
Chicago is not set up like most other cities (where there are decent places to live for families in the city proper). You should start looking in the suburbs. Virtually none of the suburbs have direct access to the El. However, most suburbs have access to Metra, which dumps you off in Union Station, which is a walkable distance for most jobs in the loop. Metra is $70ish - $140 a month for a commuter pass.
http://metrarail.com/Sched/cnw_w/cnw_w.shtml
Geneva, Wheaton, Glen Ellyn, Lombard, Villa Park, Elmhurst are all decent places to live.
http://metrarail.com/Sched/bn/bn.shtml
Aurora (eastern parts of it at least), Naperville, Lisle, Downers Grove, Westmont, Clarendon Hills, Hinsdale, Western Springs, LaGrange are all decent places to live.
I can vouch for Naperville having really good schools. It was also rated very highly in the country for 'best place to raise children'.
Since you're moving from kansas, you can plan on your housing costs doubling (or more than doubling) in price for a given home. If you want to live far from the city (and by far, i mean 1.25 hours by car, prolly like an hour by train), you can maybe get 1.5 times what you're used to. So keep that in mind. Also plan on your food costs increasing by 25% or so, at least.
Other than being an expensive place to live, it's nice. I'd take a long weekend and fly out and rent a car. drive around a bit, and you will get the feel for things.
Hope this helps
ebaycj