In general in Wisconsin, any numbered/lettered highways west of I-94 from Minneapolis to Beloit are solid. Most have average to above average surfaces and rolling topography.
Not sure exactly how to structure this so I will try a few different formats. For Chicago area folks wanting a relatively quick starting point, I would take the fastest route possible to Beloit.
Here is a sample route from Beloit sticking to numbered and lettered highways that will take you to arguably 3 of Wisconsin's best small towns, including New Glarus (Brewery) which in general is a fantastic jumping off point for taking drives west.
https://goo.gl/maps/jEkb53hMxgwsb9bc7
A sample route west of Madison. I've driven all of these..
https://goo.gl/maps/cg528DVMCwrCxeHW6
Let me know if this kind of stuff is helpful.