If you're looking for a meeting place or a good stop around ½ or halfway between Louisville and Sonora, you can try Belmont, KY, which is about half an hour south of Louisville, or about half an hour north of Sonora.
Another possible place to stop near the midpoint is Lebanon Junction.
About ¼ or a fourth of the way, you can stop at Okolona, KY. This is about 12 minutes southeast of Louisville.
About ⅓ or a third of the way, you can stop at Gap in Knob, KY. This is about 18 minutes south of Louisville.
About ¾ or three fourths of the way, you can stop at Elizabethtown, KY. This is almost an hour south of Louisville, or about 14 minutes north of Sonora.
If you drive straight through without stopping at all, the total distance is 57 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 55 minutes.