My Christmas layout is made very similar to TedW's. Structurally, it has held up well for 3 years. I then added cheap indoor outdoor carpet under my snow blanket, with FastTrak on top. The sound is deadened some.
For my "permanent" layout modules, I'm using GarGraves on cork on used Homasote. It isn't as loud. I want to be able to hear those expensive sound units in my scale engines.
Adriatic, Palm Pond!! I love it!!!