In that case Crawfish Town at exit 115 is good. Take the exit and go north for about a mile. It'll be on your right. I think the parking was meant for tour buses, but trucks park there. I've done it plenty of times. Call and see what time they open. If I remember correctly, they open at 15:30, but don't hold me to that.
There's a restaurant that's part of the same building as USA truck stop on I20 exit 103 in Calhoun Louisiana. It's just west of West Monroe. I don't think it's anywhere near the best Cajun food but it's not bad.