You could always access the raw XML of the feeds and create your own method to parse them and save the important sections to disk.
Something like this Chrome extension is helpful in accessing the XML for different feeds that you have active in the reader.
Having this raw information will get you whatever content that the blog was exposing to the world, but it won't necessarily get the entire blog from top to bottom. Running something like httrack would allow you to download the entire blog for offline viewing.