Lake Michigan has some amazing lakeside cities on your way down.  I suggest stopping at Port Washington and walk the beautiful lakefront park at the Port Washington Marina where you can see the fishermen come in with their catches for the day.  While there you have many amazing restaurant choices but I recommend Twisted Willow Restaurant, the service is excellent and the food spectacular!  Make sure you have the table side s'mores dessert where you can roast your own marshmallows and and the chocolate of your choice.  We have it every time we go.  If you're into Mexican food there's also Beanies Mexican Restaurant where you can swing on a swing at the bar or enjoy an amazing margarita on the patio.  Both restaurants are within walking distance from the harbor which by the way has free parking!

 Further down the coast, you could stop in KenoshaThey also have a beautiful lakefront walk and harbor. There you could sample great Irish food at Ashling On the Lough the Molly Malone Mussels are the best!  The choices between seafood and beef are all top notch from Bangers and Mash to The Shannon River Salmon all while viewing the harbor activities.  One note: every Saturday 9-2 they have an amazing farmers market, one of the best I've seen, next to the restaurant so it may be difficult to get seated at that time.  Kenosha is also an easy drive to Great America. Enjoy the New Goliath and your day at Great America!

Stop for brunch in Madison at Madison Sourdough Co. It's fantastic food, and the outdoor seating is lovely. Grab some pastries and drinks to go on your way out too.

Check out the Harley-Davidson Museum® and stop by Coquette Cafe for lunch or dinner. Make a stop at the Milwaukee Public Market for some edible souvenirs from Milwaukee

Hi Sam! I'm from Milwaukee, and my friends always enjoyed stopping at the Mars Cheese Castle on the way down. It's touristy, but very "Wisconsin". Enjoy!

There's a very nice restaurant just about ten minutes south of Great America on Waukegan Road.  It is called Grille No.43. It is located in Lake Forest.  The food is gourmet but not too outlandish.  Small place with nice service

Whatever you do, you have to stop at the Mars Cheese Castle! I'm talking cheese curds, sharp cheddar spread, and beef sticks! Pure deliciousness. Trust me, you'll want to make this stop.