If you're that close, really should go. I drove to Madison a few years ago when it was there on a Saturday, Racine many years before that and Miller Park was the first time, back in 2005. Just to walk around, like a large car show with some vendors and some nicer than usual cars, if anything.
My LS is ready to cruise and no plans to tear into anything so it should be good in June too. The SS is under the knife with a head upgrade and a few more things I want to do, not sure it will all get done by then. Wagon would make a good power tour vehicle but as fun as it is, rather drive the other two since the 3.8 gets worse mileage and I don't think would be as enjoyable in it's current form for a long drive compared to the others. Maybe in 21' since it would likely start in Madison and be very local. And I have a few things planned for it as well, not sure where I'll be at by May/June with it.