Why don't you call the head baseball coach at Stevenson to get his viewpoint on top programs? I'm sure he is accessible via email or voicemail.... And think, you could put in the word for your children for the coaches to be on the look out.
Deerfield is next door to Stevenson and I played on the team in HS as well as the little league Deerfield youth baseball
www.dyba.com which is a good program. I don't think Lincolnshire has a little league but I could be wrong. But if your kids are seriously talented, they will need to make a travelling team to face serious competition, so a Deerfield travelling team would be the way to go vs. an in-house league. This will all need to be on the merits/talents of your kids though....