Earlier this year, I discovered my favorite "organizational" item for craft shows. This wide, 3-drawer plastic bin:
I actually already had them on hand and were empty (back when I was trying to get rid of the "college-dorm" look of my house). I've discovered I can fit all of my inventory in one, they fit beneath every type of table out there (even the short ones), and they are extremely easy to transport when I put it on my luggage roller. The wide drawers are nice because I can fit up to 6 small shadowboxes or 4 wall hangings+12 ornaments in a single drawer and still have a drawer for all of my small stuff (jewelry, bookmarks, notecards, etc).
Now, time to figure out what unfinished project is to become the gift for a raffle at the event!