To add to my above post, having a little more time;
From the Galveston jetties to Grand Isle is a route I have used: however, mostly for powerboat deliveries. If you can see two or three days of north wind, NW to NE in the winter, I would not hesitate from Galveston, staying along the beach to the mouth of the Atchafalaya, inside(north) of Ship Shoal, then on to Grand Isle. From Grand Isle go east to an entrance known as Tiger Pass(use only during daylight), about 15 miles southwest of Venice. Grand Isle and Venice have very good facilities, although somewhat powerboat oriented, they don't mind a stickboat. Up Tiger Pass to Venice, jump the river across to a pass known as Baptiste Collette. About a ten mile run will put you in Breton Sound. From there up to Biloxi-Gulfport inside the Chandeliers and there you are. Once you are in Breton Sound, the "hard" part of the offshore oil patch is over, and the water, all of a sudden is green. You are now, East of “The River”. Beat the daylights out of all those tows, locks, Morgan City, New Orleans, etc. HEAVY Oilfield traffic at most inlets; Sabine, Cameron, Freshwater Bayou, AND THE BUSIEST at Belle Pass, Port Fourchon, 24/7/365. And a “MILLION” platforms and their satellites on most of the entire trip. I would not be off of Belle Pass at night. Oilfield boats, one after another. The Tiger Pass/Baptiste Collette route has been a “secret’ shortcut for decades, and I see more and more pleasure boaters each year. Beats going around that Delta, which is, in my mind, a NO-NO for a sailing vessel. Just too much going on. Entire trip with an experienced crew, and the shiniest radar reflector, and the latest and greatest radar you can afford, at or visible from the helm. In another thread PBZeer suggests, Galveston to Calcaseiu, may I suggest, Galveston to Freshwater Bayou, through the locks, then a 15 mile trip up to Intracoastal City, that puts you at the 160 WHL. Another option is coming up the Atchafalaya and Bayou Cassotte putting you east of Morgan City. I’ve used em all, weather, radar, and experience being the deciding factors. There is always that 360 mile ditch run and a THOUSAND tows. UGHH.