Thanks to not looking at the map on the way back but relying on signposts, we ended up missing the turning from I-10 back onto I-49 and went about 80 miles too far along I-10 ending up in Westlake, LA. Instead of going all the way back to Lafayette, we turned north onto US-171 and then cut across back onto I-49. In all the whole trip back was about 8 hours long in spite of the wrong turning.