I am writing this as a guide for my wife who will be driving to Marscon with my kid:
Section one: Wood Dale, IL to Madison, WI (121 miles)
Route: I-290 west (5 miles) to I-90 west (50 miles) to I-90/I-39 (66 miles)
route issue: I-290/I-90 junction. Interstate 290 expands to as many as 5 lanes at this point. The left three lanes bypass the exit; stay on the right side. There are three exits on the right. The second one is Interstate 90 west. After doing a 270 degree turn you will be on the Northwest (now called Jane Addams) tollway through most of Illinois.
All tollbooths now allow IPass so if you are on the correct side when passing a toll booth you will not need to stop.
Stopping: Some exits on the tollway do not have an entrance ramp going in the same direction. There are signs posted mentioning that. In Belvedere, half way between Rockford and 290 there is an oasis which has gas, toilets and places to get food.
In Wisconsin, the biggest concern about stopping is making sure there is a place near the expressway to stop. The rest areas only have toilets and vending machines. Exits which have food and gas do have blue information signs about a half mile from them. However, it is highly recommended to stop at an exit which has the places just off the exit. Some places are up to 2 miles away. Also make sure when getting back on the expressway to take the correct direction. (West heading to Bloomington, east heading home).