C09 - KDKB
I don't fly IFR, just VFR so I don't think this will help you much. I fly this route quite often from Lafayette and Monticello Indiana to Stoughton WI. This will keep you out of the class B and set you up to stay East of control areas for Rockford, Janesville and Madison (per Notam recommendation).
If the weather is nice and you want to take the scenic route take the low VFR route along the lake shore. You need a Mode C transponder and stay under the Class B but it is a great view of the city. You can cut inland north of t he Class B and stay to the west of KMKE.