I always suggest for anyone who will be in the Northern Indiana area to stop in on
Das Dutchman Essenhaus in Middlebury, Indiana. It's not that far from Elkhart and well worth going there for lunch or dinner. They are closed on Sunday. You won't be disappointed. Explore the little shops and just have fun.
Jayco, Coachmen, Shasta, and Starcraft RV manufacturing plants are also located in the Middlebury address. Might consider an factory tour from one of them too. Grand Design is just North of Middlebury, right off of I-80 and US 131.
On your way there if you take Highway 20, you'll probably pass Riverside Retro RV, Dutchmen, and KZ Manufacturing.
And there are still several RV manufacturers in Elkhart.
You can travel the East-West back country roads that parallel Highway 20 and you will see Amish homes, horse and buggy, and several small business run by Amish families.
Here's a link to some interesting sites in the area:
Click here.If you don't mind driving the other direction, to South Bend, there is also the University of Notre Dame. To see the chapel there, by itself only, is well worth the drive.