Layout Base Lionel

 Its looks like plaster sheets.  As long as you remove the plastic film from the pink foam, you can glue scenery material right to it.

I typically paint my foam a  flat dark brown color, and add grass etc while the paint is wet. Later I soak it with 50/50 glue water mixture.

 Using coarse turf will give you a "wilder" look. If I want to make small hills and elevation changes I use Woodland scenics " Mold-A-Scene" plaster. Its a "grainy"  thicker plaster type mixture that can be shaped.

Theres really no wrong  way to do it.