We went to Homestead Orchard in Woodstock a few weeks ago http://homesteadorchard.net/. We had a great experience. It is simply an orchard, no jumpy castles, pony rides, petting zoos, etc. So we went, picked apples and raspberries and the kids ate some apples on a big wooden swing, and we left (there is an outlet mall nearby, with Carters, Childrens Place, Osh Kosh, etc and we went there afterwards). We had a great experience. I know on their website they recommend going in the morning because they sometimes get picked out by the afternoon in certain varieties. If you call the owner is very personable and can let you know what is ripe, etc.
We also went to a very old orchard in Michigan City, but that it quite a hike, we were there for other reasons, but if you are going that way, let me know and I can give you information on a couple of orchards in Michigan City.
Our favorite "big" orchard is in Hobart, IN and is called County Line Orchard http://www.countylineorchard.com/ They are huge and very friendly. It gets crowded in the parking lot and the store, but the orchard is so big we don't feel like it is crowded when picking and we feel like it is well managed. It takes about an hour to get there from the city. They have a lot of activities for the kids and they have concerts almost every weekend. This is definitely a place to go when you are making a day out of it.
We went to All Season's Orchard, which I saw someone recommended, last year and we were very disappointed. It was extrememly crowded and it was not well managed so there were lines everywhere. Plus, I thought the employees were rude. They actually searched our trunk when we left to make sure we hadn't picked any of their more expensive apples and hid them in our bags.
Good Luck,
D.