The Indiana Dunes State Park on the souther shore of Lake Michigan is a nice day trip. One could make a 2 day hiking adventure out of it, but after walking the trails, you are going to get tired. I will explain why later. Lake Michigan is the first Great Lake I explored outside of the Niagra Falls setting. It really does feel like an ocean shoreline. The waves are piddly, but the size, scope and horizon shout "ocean". The beach lacked seashells and seaweed, but the constant waves could fool you if you closed your eyes.
The trails are all nature preserve trails which means no "wood boards" to make walking through sand easier and no benches occasionally or cleared out areas to chill. You hike the trail for its entire length through soft sand. I am OK with that, but I also go to the gym often. Walking through soft sand is hard work. There's a rap song that says "trained to run 20 miles through soft sand" like soft sand makes running tougher. These hiking trails are miles long and are through soft sand. The average American, especially if from one of the surrounding states or Indiana itself, is probably overweight and out of shape. They will need a bench or rest area. After multiple trails and lots of walking on soft sand, I needed a bench.