On the corner of 137 and 21 in Libertyville the Wildberry restaurant is a good alternative to Walker Brothers (which has a location on 21 in Lincolnshire just south of 22).
At the corner of 21 and 41 there are a couple real good breakfast spots, The Point, they make great skillets! and Fat Man Inn, a biker bar that actually puts on a great breakfast for $7.00. I lived in Gurnee for a couple years and between the family restaurants at Grand and 21 (In Laws, which has the same management as Fat Man, and Avalon) I'd go with Fat Man any time!