We stayed at Fountainbleau a few months ago, and you DEFINITELY want the new section. We got stuck in the old one, and had a hard time maneuvering into the site.....even with a small Class C. The utilities are also on the wrong side at some sites. When we drove through the park and saw the new section, we were REALLY disappointed with where we were at.......especially since there were so many open sites in the new section. If we had been staying any longer than two days, we would have tried to move.
As to food, I'm more familiar with the places near Breaux Bridge and Lafayette, but just look for anything with the word "Cajun" in it! You definitely want to try the crawfish boil, boudin, shrimp etouffee, and whatever type of gumbo they happen to be serving that day (sausage, chicken, seafood, whatever). For breakfast, try to find a place that serves fresh beignets (fried dough with powdered sugar) and couche couche (kinda like cornbread served as cereal with milk and sugar or molasses). I don't think that I EVER found any Cajun food that wasn't worth remembering!
While there, ask around for any neighborhood bars that have live Cajun music. It's worth standing in line for.
Have fun.