Let's see - I somehow feel like the kids are leaving quite a few blanks in their reports. Randy has been the main driver, and I think it wipes him out so he isn't helping here either. So...
Day 4: I already wrote about that - Billings to Chamberlain, South Dakota
Day 5: Chamberlain to Madison, Wisconsin, where we stayed with my sister and her husband and two kids. We took mostly I-90, but jumped off in LaCrosse and took some back roads through Westby, Viroqua, and Richland Center.
Day 6: We hit the road late because we wanted to visit a little longer, but still made it from Madison to Warsaw, Indiana. We took Hwys 12, 47, and 30, because we were completely sick of the interstates. I wouldn't recommend 30 as a way to avoid Chicago though - sprawl hell. Much nicer after we got past Valparasio.
What might need explaining? The dog park was in Sioux City (we just stumbled upon it, lucky us), the blizzards were too big, the macaroni and cheese was fried, and I really did knock the water glass into Randy's plate. I know nothing of the Yogi Bear episode, I was in the front seat. Oh, and the "creepy fairy tale land" was some sort of 1800's-themed amusement park. Even the gas station was themed. And it was late, and un-manned, so it looked abandoned, but shiny new all at once. It was creepy!
And since you've been asking how Willy travels, I attached the photo. And Dave, sorry about your lawn. Wouldn't you know it, that's the only place he's left such a mess.