I am trying to answer but keep getting flagged as a robot, so I am trying to go back and edit and post the full message:
I second what padredw said, while I have not stayed at Riverview, it does seem to be a nice rv park, with friendly owners who I visited at a local RV show a couple of years ago. Lots of history in the area, my mothers side of the family is from the Louisiana side near Natchez. If they are open the day you are in Vidalia you might consider going to the Louisiana Delta Music Museum or the Jerry Lee Lewis museum. As to the food side of things, you can find a lot of good food where the locals eat anywhere in the area, though the area around Natchez is 40 or 50 miles too far north to reliably find good cajun food, you can still find good southern style food there. There is also a good donut shop in Natchez about 3/4 mile from the bridge, at a strange angle X cross road, they put out fresh donuts about 5 times per day. The best Cajun food is found south of I-10 between Houma and the Texas state line, note that stuff they serve in New Orleans is not Cajun food, at best it is a Cajun / Creole mashup, and no Creole and Cajun are not the same thing, they are as different as Thai and Japanese food.
Now for places to eat around Avery Island, for fancy Cajun Food, try the Cafe at Rip Van Winkle Gardens at Jefferson Island (about 20 miles north of Avery Island) https://www.ripvanwinklegardens.com/ For down home hole in the wall cajun go to Suire's Grocery http://suires.yolasite.com/ at the intersection of 35 and 335 south of Kaplan, best of also all they have frozen single serving portions that you can take with you and heat up later. If you go there take a peak into the public restroom, it is the smaller than some RV bathrooms. Also if your schedule lines up check out the Dutch oven sampler meal often held at Palmetto Island State Park https://www.friendsofpalmetto.org/events-1.html
One more good traditional Cajun place in the area is Landry's in New Iberia, not relation to the fake cajun regional / national chain by a similar name http://landryscajunrestaurant.com/
I can name more for you, but these are the ones that come to mind within a half hour or so drive of Avery Island