I spent the better part of an hour scraping the old cork of the plywood, to see if it could be salvaged. I now have some skin of my old knuckles. Facit: New Plywood tops with 1/2 inch pink foam as a subroad bed and then Woodlands Scenic Roadbed instead of the cork. I have been using this product on my N scale layout previously and it works like a charm.

I have permission from Mark Stutz to use his plan for my Layout. If you can speak German you can follow it on my links site under Schnellenkamp/Forum.
I will have to "tweek" it a bit since one wall of my layout does not have the window as shown in the plan.