Any promotion of the kilt is a great idea. I've done a few such booths myself.
What Colin says shows great wisdom, if you can enlist the support of kiltmakers (sample kilts, accessories, cards, stickers, posters etc to display) or work with a related organisation (New World Celts, St.Andrew Soc, Caledonian Soc.).

I'm sure any of these groups would appreciate someone with your motivation and enthusiasm.

I'm doing the same at present, trying to organise a festival to celebrate Tartan Day (July 1 here).
I'm approaching local groups, councils, mayors, Pipe bands and retailers to make it happen.
some jobs are just too big to do alone, mind you, getting others to share your passion can be an uphill battle.