If you're looking for a meeting place or a good stop around ½ or halfway between Racine and Bluffton, you can try Portage, IN, which is a little over 2 hours south of Racine, or about 2½ hours northwest of Bluffton.
Another possible place to stop near the midpoint is Valparaiso.
About ¼ or a fourth of the way, you can stop at Chicago, IL. This is a little over 1 hour south of Racine.
About ⅓ or a third of the way, you can stop at Hammond, IN. This is almost 2 hours south of Racine.
About ⅔ or two thirds of the way, you can stop at Plymouth, IN. This is about 3 hours southeast of Racine, or almost 2 hours northwest of Bluffton.
About ¾ or three fourths of the way, you can stop at Warsaw, IN. This is about 3½ hours southeast of Racine, or a little over 1 hour northwest of Bluffton.
If you drive straight through without stopping at all, the total distance is 253 miles. The distances shown above don't include local roads to get into each town, so if you're planning a long road trip, make sure you factor in traffic and road conditions, rest stop breaks, and interesting detours along the way. If you're in a rush, you can do the trip with zero stops, and your total travel time would be around 4 hours, 50 minutes.
