As I get older I find that module weight becomes more and more of a factor in determining which modules to bring to a set up. We got a four foot module that has exquisite modeling on it and is a real hit at the shows. Unfortunately it is way over built and weighs a ton. So it is not the first one we grab when we go to a show and most of the time it gets left behind. We have embarked on a campaign to build modules light and strong versus heavy and strong. Also we are going to a six foot module to reduce the number of joiner tracks. The additional 2 feet of module will add some weight but six foot modules gernerally require two people anyway due to their bulk. Lacking any of the tools needed to process plywood into dimensional lumber we have elected to go with an outer frame of 1X4's with interior supports made from 1X2's. The frame is covered with 1/4" underlayment. Placement of the interior supports is critical to prevent the roadbed from sagging. The first interior support is placed 6 inches from each end to prevent the "ski jump" at the end of the module. Then annother 1X2 is placed every foot. In addition to saving weight the use of 1X2's allows the wiring harness to be stapled to the underside of the supports rather than having to drill holes through the supports. All pieces are sealed before assembly and then fastened together using screws only. No glue is used. This allows relatively easy repair of a module should it warp or rack. Scenery is made from extruded foam and use of plaster is verbotten. We did allow a limited use of Scultamold but lately have been advocating the use of a lite weight spackling compound. We like the new modules with the weight reduction.