Hi Tad,
In general, we always use a different program for every event. This helps us track registrants and people who attended our booth for each individual show. This will also be easier to set up default reports and find the specific data you're looking for.
I would recommend creating a shell program with the basic campaigns/assets that you will need for each tradeshow, and cloning it and editing it for each tradeshow. Perhaps you can organize them in folders by month and year if you have very many, and archive them once they get older to clean up search results.