Stamp Shows Primer
You've asked questions regarding shows for both Juniors and Seniors and no one has answered. Here are some links to help you find out about shows.
Here are the shows which are listed with the APS: Show Calendar. There are none listed for Louisiana. Here's an introduction about stamp shows: Shows and Exhibitions.
Unfortunately there is no magic formula for holding a show. The APS publishes a book on the subject of Running and Promoting Stamp Shows compiled by John Becker from 1995 APS-sponsored Show Organizing Conference 50 pages, spiral bound booklet, $7.50 retail, $6.00 member price that covers Planning, site selection, budgeting, security/liability issues, exhibits and judges, bourse dealers, promotion/publicity... a complete how-to-guide for producing a stamp show. A useful planning tool for any current show chairman.
Here is some information on what it takes to exhibit; Information about Exhibiting. There is also some good information available for those who need something Just for Kids.
To get a stamp show started you need some resources: people, money, energy, and leadership. Sources of leadership may be found among APS Chapters (I found 5 APS Chapters -- probably all of the stamp clubs in Louisiana). New Orleans has one, Crescent City Stamp Club of New Orleans, which you probably should make arrangements to visit. Also essential to leadership are: Dealers. The venerable Raymond H. Weill organization is listed in New Orleans and there are a couple of more but there were only a few in Louisiana. It is essential to have active, hardworking, and enthusiastic collectors and dealers working together to put on a decent small show.
It also takes capital. I don't think you can even start to think about a show unless you have $5,000 to $10,000 in a bankroll. You may be able to make it self-sustaining but it takes some startup to get you through the first few years. A hall for 3 days will cost $3,000 to $5,000 or more. You'll be extremely lucky if you find some free for non-profit organizations building to use. You need to pick a date which fits the local "season" and doesn't conflict with existing shows. If you plan on exhibits, you can invest another $10,000 in frames unless you can find some to rent or buy cheaply. (You'll also have to decide how to store between usages as well.)
Holding a show is rewarding and great fun but it isn't easy. It takes the work of a lot of dedicated collectors and dealers to pull it off. (I was a volunteer with Rompex for a number of years. Now, I'm only a small time player in a small-time local show.)
You also asked about shows for Juniors. I would suggest you contact the people at the Young Stamp Collectors of America.
End of firehose! Aren't you glad you asked? :-)