When you get to south La., find your way to New Iberia and check out the Tobacco plant. From there make those left turns as mentioned and go to Cameron, La where you will take a short ferry across the river, keeping west bound on the coast hwy 82 you will cross into TX at Port Arthur. From Port Arthur you can work you way over to Winnie, TX and head over to High Island, TX and run the coast over to the Galveston Ferry.
A little side trip would be to head south from Port Arthur to Sabine Pass, turn west on the coast hwy to Sea Rim State park. Winter is a good time to visit this area as the mosquitoes can be ferocious with a south wind pushing them out of the marsh towards the beach when it’s warm. Unfortunately the road further west has been shut down for many years so you must return to Port Arthur to get to Galveston.
Have a good trip.
Patrick
Semper Paratus