I downloaded Airport Design Editor. After you get it installed, File -> Open Stock Airport. You type in the airport and before you open, below it will tell you the file path and the .BGL file - something like "APX15150.bgl".
Go to that folder path, grab every file with "15150" in it, and put that in a folder structure like this in the main P3D directory:
\Addon Scenery\KPDX_Test\scenery\
Dump everything in that scenery folder that contained "APX15150.bgl".
Add scenery pointing to that folder like you would a normal third party scenery. Put it above the ORBX region.
Now, everything looks normal around the airport in regards to the ORBX region (this was for KBVS), but the airport is default and has the Worldwide HD textures.
Sorry for the quick response, my nearly 1 year old daughter is trying to help me type!