*I am sort of just stumbling around with all of this, so you've been warned*
I was in the middle of running my 7th build and writing a forum post asking for help but I just got Admob to work and thought I'd post my solution here for my own reference and for others reference.
1. Export Project utilizing admob and properly setup IDs within construct 2.
2. In the export destination folder in the www directory, open config.xml
<gap:plugin name="cordova-plugin-ad-admob" source="npm" />[/code:pfsge9j5]
4. Save config.xml
5. Zip up the package, upload to Phonegap, download the .ipa and run.
Both interstitial and banner ads work great, although banner ads seem to not show when overlap is turned off.
Update: Adding the plugin per the official Scirra tutorial in Intel XDK returned an error during the build.