I'm shooting a roll of Fuji Provia 1600 at 800 ASA right now with my Nikon F90x.
Why don't you do a small test at home? Shoot one slide film with the Nikon F4 exposure meter at + 1/3 stop and with Matrix metering. Find some settings you'll hope to shoot in New Orleans, take some shots (street, marketplace, people, building, store window, parked cars, ...) and get the film developed before you go New Orleans. Are the results satisfactory to you? If not, what to adapt?
An other test could be to bracket some shots at locations with challenging light: -1/3 stop, normal, + 1/3 stop and compare.
You could also use the "Program" setting and shoot the same scene metered with a hand meter to see if you can outdo the Nikon F4 ;-)
This way you get to know & trust your camera and the film before you go for the real thing.
And don't forget: have fun and post some images later when you return.