Last year was my first SW La Mardi Gras experience. I tried to get to as many places as possible, and it was all good. No matter where you go or which parade, your 4 year old will come away with more beads that you can carry. A couple observations: Lafayette - tons and tons of beads, floats, and a little more urban. Eunice - horses everywhere, Church Point - local community fun, boudin cooking on every corner. Didn't see the Iota parade, but the festivities, lots of home cooked food, local musicians. No matter where I went, I saw nothing you wouldn't want a four year old to see.
Check out this link:
http://www.arnb.org/Mardigras.php
I used it last year to plan my week around who I absolutely had to see. Have fun!
Steve
In Lake Charles, the saturday before Mardi Gras, they have the Childrens Parade. As a matter of fact, the entire weekend before Mardi Gras is very family oriented here. Gumbo cook-off($5 gets you all the gumbo you can eat from about 75 different cooking teams), Krewe of Barkus parade(Dogs dressed up in Mardi Gras costumes: the kids love this one), Taste of Louisiana, Daytime cajun and zydeco dances without alcohol, etc....I have 2 kids, ages 4 and 7, and we've been evey year to everything. Their Daddy even took third place in the gumbo cook-off a couple years ago. At the childrens parade, tons of throws and candy, they kind of tone down the horns from the Trucks pulling the floats, and the parade route is at least 6 miles long with plenty of places to set up.
I don't know off the top of my head, but all you have to do is find Ash Wednesday on the calendar, and you will know that Mardi Gras is the day before that.