I cannot see how to load the digital gpx files from the ACA.Detailed instructions available on Adventure Cycling web site.
From a location where you have the GPX files (GoodReader or Dropbox), you can open them in EasyTrails app.
I have downloaded the recommended Easytrails app onto the IPAD, (free version)This maybe part of the problem. The free version only supports loading one track. You should be able to see it from the "paw" icon at the bottom of the screen.