Taking US35 north out of Laporte, IN, there is a turn off to the right on IN39. Twisting through the country side, you will cross US 20, go under the Indiana Toll Road, into Michigan (where it becomes MI239), over I94, then dump you out on US12. The road isn't as spectacular, but the end destinations are outstanding.
Well paved road that dumps you out 1/2 block from the Lake Michigan shoreline, and 3/4 miles from Redamaks, the Legendary Hamburger joint recently on Netflix. The drive is sweeping turns, and a few stop lights, but mostly wooded countryside and meadows.
There is a portion around the toll road that is 4-lane up to US20. Otherwise its a good road with light to moderate traffic. You get to avoid all the major interstates and busy US highways.
There is a park at the lake shore that you can enjoy. This area is a great tourist area. Breweries, restaurants (Redamaks and Stray Dog are the most popular), shopping, ice cream shop (Oinks is awesome!), and the beautful Lake Michigan. Oh, yes, don't forget the 4-Winds Casino at I94. Before the state line in Indiana is the Hesston Steam Engine Museum.
Nice quiet alternative to Interstates, although it passes two of them. Country drive, Lots to see and do in New Buffalo. Road conditions are good, and little traffic. If you follow IN39 south out of Laporte, you end up at Kierstings down by North Judson. Great shop and motorcycle museum.