This is not super easy, but I accomplished it. Download one bundle at a time here (m4a works):http://www.drabblecast.org/downloads/
And then extract the bundle (using a zip or file manager app) to Pocket Casts' "custom files" directory:http://www.shiftyjelly.com/support/pocketcasts#115
Then, when you're in the main "Podcasts" view (not "Audio" or any other filter), there is a special fake podcast that shows up, containing files in that directory.
I've listened to 1-110 and 266-present. Taking a break now to relisten to The Lost Cat Podcast since it just got a second season.