Tim Harris from the Orbx dev team has made a very handy interactive KMZ file which you can load into Google Earth to get an idea of the extent of the FTX PNW region coverage, plus toggle features such as airports, NDB, VORs, photoreal mountain peaks etc.
This is version 1.4.2 of this KMZ - Updated 13th Jan, 2010.
Usage: simply save the .kmz file attached below, to your local hard drive, then drag it into Google Earth.