Perhaps a more basic question to discuss first is whether we want to try for a (i) collaborative display where everyone follows the theme and all contributions are planned in advance to work together; (ii) a semi-collaborative display where there is a “theme” but anyone who wants to bring something outside of the theme is welcome to do so; or (iii) wide open (a la KidsFest) where everyone brings whatever they want and we just put it out together.
I am leaning towards (i) or (ii). Train shows generally are looking for a more cohesive layout, not just random creations laid out on a table. If the theme is “Winter”, we could work in just about anything, not just town and train stuff (although that is what I will be focusing upon).