ftauss, when you mount these to the foam board or masonite, you can leave a few inches at the bottom blank. That lifts the buildings higher so the trolley will not block the view. A fence, trees, or other scenic details can be placed between the buildings and the trolley track. This gives "forced perspective" to the scene so the buildings look like they are in the distance. To cover the full six feet you will need more than one of the "main street" sheets. The "western town" buildings also look good like an older section of your main street. You can either have a painted blue sky on the 6 x 1 1/2 foot masonite, or if you cut the buildings out a blue background can be placed behind the cut out buildings. This too will increase the illusion of depth.
I am sure your coworkers will be impressed with your display.
Paul Goodness