Cecils is good, but not much of a parking option for motorhomes, not much parking option for cars either (old downtown building with only parallel parking out front), there is also Steamboat Bills in town (SW Louisiana small chain with a handful of locations) is fairly good too, more limited menu mostly fried stuff (shrimp,oysters, crawfish tails), but also some non-fried options, Gumbo, Etouffee,.I feel Steamboat Bills overpriced for what you get ($16 for a large bowl of shrimp gumbo), though they do have some good deals on weekday lunch specials and much better parking for an RV (former Ryan's Steak house building which was built in the 90's), also it is next to the city park which has a free dump station if you need it.
Between the two I would tend to say Cecils probably has the better/fancier food (steaks, etc.) options, but is more of a contemporary take on cajun food, and has a number of not particularly cajun items on the menu (Burgers, Asian Chicken Spinach salad, turkey club sandwich, etc.), Steamboat bills has more of a working class Cajun roots, their original location in Lake Charles has been there for 40+ years, and until recently it was an order the counter kind of place, the local location here started having waitstaff and ordering at the table service in the last year or two, perhaps to justify their prices, about the only thing on the menu that I would not call cajun is the breaded fried chicken strips and maybe the fish tacos. This time of year Steamboat bills probably has boiled crawfish too, boiled crawfish season usually starts the second or third week of January, but the weather has been so mild this year that some crawfish places were open for new years, though early season crawfish are often on the small side, so a lot of work for not much meat.