If you're looking for a meeting place or a good stop around ½ or halfway between Louisville and Vine Grove, you can try Limestone Springs, KY, which is about half an hour south of Louisville, or about half an hour northeast of Vine Grove.
About ¼ or a fourth of the way, you can stop at Okolona, KY. This is about 13 minutes southeast of Louisville.
About ⅓ or a third of the way, you can stop at Brooks, KY. This is about 15 minutes south of Louisville.
About ⅔ or two thirds of the way, you can stop at Lebanon Junction, KY. This is about half an hour south of Louisville, or about 17 minutes east of Vine Grove.
If you drive straight through without stopping at all, the total distance is 48 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 52 minutes.