What are the expansion/contraction properties of a good foamcore product?

I assume you have lots of experience with that 3A product you use most extensively, Prof Klyzlr??

I am wondering about attaching my track directly to a 3/16" thick foamcore that would cover the entire surface of my 3/4" plywood deck, then using a sharp razor to cut out various shapes under certain structures and scenic areas that it might be desirable to remove as an entity to temporarily work on in a more open environment.

I'm getting ready to ballast my first ever section of track.  I did a search of this forum and found countless excellent discussions of the subject.

However, I didn't learn where to apply the diluted glue.  Do you lay a strip between each tie (I assume)?  How about the banks of the cork?  Does it migrate there, or do you also apply some there.

When pre-wetting with the alcohol/water mix do you apply it with an eye dropper, or do you just spray the overall section?

Thanks for your help.

Deane

So, I'm in the process of designing my new layout (large scale outdoors) and workshop space in the new house, and I've got a design problem, I need help with. 

I am currently building my tracks with EZ-track snappable from Bachmann.

I am focusing on the control aspects.

How can I add realism to this later on, like adding sand, grass, paint, etc.?

Is there difficulty in doing this? Anything that I should be aware of as I build the current roadbed with EZ-track?