If you're looking for a meeting place or a good stop around ½ or halfway between Houston and Jackson, you can try Lafayette, LA, which is about 3 hours east of Houston, or about 3½ hours southwest of Jackson.
Other possible places to stop near the midpoint include Hope, Sparks, and Butte La Rose.
About ¼ or a fourth of the way, you can stop at Lake Charles, LA. This is about 2 hours east of Houston.
About ⅓ or a third of the way, you can stop at Jennings, LA. This is about 2½ hours east of Houston.
About ⅔ or two thirds of the way, you can stop at Shenandoah, LA. This is a little over 4 hours east of Houston, or a little over 2 hours south of Jackson.
About ¾ or three fourths of the way, you can stop at Montpelier, LA. This is about 5 hours east of Houston, or about 1½ hours south of Jackson.
If you drive straight through without stopping at all, the total distance is 443 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 6 hours, 32 minutes.