I am starting a new project and I am not sure as to what should be the base. I have 1/4 plywood as the solid base with a 2" extruded foam on top of the plywood. I have read some post that just use the extruded foam and lay their track on top of that while others lay the track on the plywood and use the foam for around different areas of the layout. This layout is a bedroom layout with a |_| shaped design with the | areas as 10' and the _ being 13' long. I have seen some great layouts but nothing detailing how the initial layouts were started.