I thought that all of you who want to take the Southern Tier route across Louisiana might want to know that the Melville Ferry has been shut down as soon as the cane cutting is over this year due to budget cuts at the state level. This is expected to be a permanent shutdown. Auto and farm traffic is expected to use highways to the north and south. I DO NOT SUGGEST trying to ride on US190 to detour.
There has been an alternate route because for many years now, since the ferry was not completely reliable. When it would break down, it could take a long time to repair. You should now use only this alternate route.
Years ago, there was a plan to cantilever a bike lane onto the railroad bridge across the Atchafalaya River, but with current budget constraints, I doubt that it will happen any time soon.
There is a new bridge being built across the Mississippi River at New Roads (that was started before the budget crunch), and that might offer another opportunity there, but that won't help you get across the river at Melville.