Sal,
That is a very nice FT layout, you may want to design some access panels into your mountain tunnel runs, in several places however. You could also put a cross over in your right hand portion of the layout, adding a couple switches, if you want. I would use Command Control 048 and larger switches thru out, Larry gives good advise about switch sizes, and then you have yourself a real nice custom layout, you can now make this happen fairly easy with the new Rockwell X2 Saw, when you need to make a few custom FasTrack pieces for your track design close out. Real nice FT layout Sal.
PCRR/Dave