Grand Isle is not a bad place to use as a base for fishing reds for sure. Personally, I prefer the area between south of Belle Chase to Venice, LA. I think you have a lot more options on water to fish. All the reds, trout and black drum you want on the fly. Redfish size varies depending on the time of year. Winter is best for the monster bulls but of course wind can be problematic. Summer is hot but so is the fishing. Tons of smaller 3 - 12 pound reds, trout, black drum, sheepshead and jacks willing to eat a fly. I have a few highly skilled guide buddies in the region and they all choose to guide between Belle Chase and Venice. Not to say that there isn't good fishing in the Grand Isle area but many feel there are more options along route 23.