How "off the beaten path" do you want to stray? What direction outside the city? And those of us who actually live year-round in south Louisiana would never laugh at summer visitors...summer means fresh local tomatoes & corn, cheap & plentiful wild-caught shrimp, snowballs every day, using the heat as an excuse to drink Pimm's cups & drive-thru daiquiris, boiled crabs on the back porch....
Roberto's River Road in St. Gabriel (http://www.robertosrestaurant.net/
)Del Porto in Covington
Perino's Boiling Pot in Harvey
Rip's on the Lake in Mandeville
Rivershack Tavern in Old Jefferson
Seither's Seafood (Harahan/River Ridge area)
Sal & Judy's in Lacombe
Perino's Boiling Pot II
3754 Westbank Expy, Harvey, LA 70058
3449 River Rd, Jefferson, LA
Del Porto Restaurant
501 E Boston St, Covington, LA 70433
Rips On the Lake
1917 Lakeshore Dr, Mandeville, LA 70448
279 Hickory Ave, New Orleans, LA
Sal & Judy's Restaurant
27491 Highway 190, Lacombe, LA
Middendorf's in Manchac, have the gumbo, boiled crabs, remoulade, broiled anything, bbq oysters & homemade ice cream. New spot in LaPlace Frenier Landing. Only open a few weeks but beautiful view - located right on the lake - and great food. Hymel's in Convent is like taking a step back in time. It is on River Road and there's an extensive menu with very reasonable food. My friend's favorite is the crawfish bisque but I like the burgers and the stuffed bell peppers. I almost forgot. Go to Slidell and get a bbq beef poboy from Captain Humble's. Best I've had. Do you have an idea of the areas you will visit?
When you say, "off the beaten path," and "outside NOLA," I wonder where you are talking about. Please define. Do you mean Jefferson and St. Bernard Parish, or further out? If further out, which direction would you like to travel, and how far? Any preferences on cuisine?
Sorry to play "20 Questions," but it will help people come up with useful ideas for you.