The info given so far on I-10 is pretty current. Can't help on Beaumont to State Line. Still some construction E. of Lake Charles for about 10mi. but road is newly surfaced just some lane restrictions. From there to Lafayette, smooth as a baby's bottom. East of Lafayette to the Atchafalaya Spillway is concrete with some hop over the joints. Try to cross the Miss. River bridge @ Baton Rouge before 3PM as it gets pretty hectic at the Jct. w/ I-110. There is some construction E. of Sorrento but nothing big. Since you've got an extra day, try staying in Lafayette, several RV parks near I-10. Lots to do there and excellent dining, actually better then New Orleans. Going to Bayou Segnette, take I-310 S., Boutee/Houma to US 90(+- 10mi.) Go E. on 90 thru Avondale and then bear right on Business 90, 2mi. to Park on Right. It's a nice park even without a lot of the trees which were lost in Katrina. $9 with Golden Passport. Our favorite sites are in the 40s and 90s. Get ready to watch lots of Rabbits, they're everywhere in the AM & PM.
Enjoy and come hungry.
Dave, Miss Sue and Lucy the Scotty
00 Windsor, 40', Grand Cherokee Limited