Last week I posted a photo of a module frame with its foamboard deck installed and marked for routing. We use a plunge router and a one-inch straight bit to do the routing, which we did at our work session this last Saturday. It took two of us about two hours to get all six foamboard decks routed:

There is a 3x3 array of straight cuts in the middle of the deck, each about six inches long. These allow wire to pass under the side-to-side support stringers that will be added later (You can see them in a previous photo of a built module posted a week or two ago). The four shorter straight channels in the middle area are for looming the module-to-module interconnect cables when the modules are in their transport cases. The connectors on the end of the cables slide into these pockets and are held in by the stringers. The four even-shorter pockets on the left edge are for clamps we used to hang a curtain around the layout at the train shows. Finally, the pair of big pockets at the top are for access to the bolts used to join the modules. These are routed with the straight bit and then beveled my hand with a hot-wire cutter.
The foamboard is ready to be glued in, but we're going to wait to do a fit check of the module frames to the existing layout before proceeding. We'll be taking the layout down soon to go to the local January train show, so we'll do the fit check as the layout goes down (or back up).
Building the new legs is next.
Jim